r/NoStupidQuestions 5d ago

Do you think the 9/11 hijackers knew that the WTC buildings would collapse?

I really don’t know where else to ask this. There is obviously an overload of information about the event itself online, but one thing I can’t find out is if the hijackers intended to, or knew that the WTC buildings would collapse. Do you think they just planned on the impact and fires to be the extent of the damage caused? As far as I know, no steel structure buildings in history had collapsed from fire at that point, so it makes me wonder if they actually “succeeded” in their plan more than they intended.

Edit: no conspiracies please, that was not the point of my post

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u/Hoppie1064 5d ago

US forces found a tape in November 2001 that they released the transcript for in December 2001. You can read an English transcript here.

It includes predictions that were made of what the terrorists thought would happen, including bin Laden's himself.

UBL: (...Inaudible...) we calculated in advance the number of casualties from the enemy, who would be killed based on the position of the tower. We calculated that the floors that would be hit would be three or four floors. I was the most optimistic of them all. (...Inaudible...) due to my experience in this field, I was thinking that the fire from the gas in the plane would melt the iron structure of the building and collapse the area where the plane hit and all the floors above it only. This is all that we had hoped for.

In other words, bin Laden thought they might reach every floor above where the plane hit on each tower, but not the collapse of the entire towers.

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u/plunkadelic_daydream 5d ago

I stopped to get coffee on the way to work and people started to gather around the television. Then the 2nd plane hit. I went to work and listened to coverage on NPR. It didn’t register with me that the buildings completely collapsed until some hours afterwards. I imagined portions of it collapsing, not the entire thing because that was unthinkable.

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u/an_ill_way 4d ago

I didn't think it was possible when I watched it fall. It just split like a banana. I remember saying, that was just the top part, the rest is just obscure by dust, right?

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u/plunkadelic_daydream 4d ago

Exactly

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u/jlaw1791 4d ago edited 3d ago

There is too much weight crashing down, and that gravitational pull increasing the velocity on so much mass is multiplying how much it weighs as it hits the floor below.

It's a dynamic load. When the building is NOT collapsing, the weight being supported is considered a static load. But as it begins to collapse, it becomes dynamic.

The fires heating up the steel sufficiently weakens the load-bearing structures so they can not hold the original weight, much less the weight of untold millions of pounds crashing down... the dynamic load, and once it goes dynamic, it's gonna make the whole thing fail catastrophically.

And that's what happened the morning of 9/11/2001.

We had never seen it before in real life or caught on camera, until 9/11.

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u/MisteeLoo 4d ago edited 4d ago

Yeah, I watched live on tv, and my first thoughts were ‘The whole building? Holy shit, it’s GONE.’ Then a little grateful it hadn’t fallen over sideways. Once the first one went, I also recall thinking it was likely the second would go the same way. I don’t think anyone anticipated them pancaking, not even the monsters behind it.

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u/External-Piccolo-626 4d ago

The fact they didn’t topple sideways is amazing engineering, as awful as it was I can’t imagine them falling sideways, just thinking about how tall they were boggles the mind.

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u/BettyBarfBag 4d ago

I'm no engineer, but I recall hearing that the centralized elevator shafts were critical in the towers falling down, rather than falling over.

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u/MisteeLoo 4d ago

That makes sense. It would almost act like a fireman’s pole.

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u/graceful_mango 4d ago

I was on my way to class and heard about the building getting a hit a few minutes after the first plane. When I got to my friends house to watch the news they were about to replay the first tower collapsing when the second tower collapsed and it took several minutes for it to register in my brain that i was watching everything live.

My one class before they canceled the day and evacuated the campus (of 50k students and faculty) had a teacher from France with Opinions who used the hour and a half to rant about America. Maybe not the best way to read the room.

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u/bouncypinata 5d ago

Imagine the damage if it toppled sideways rather than falling within itself.

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u/Hoppie1064 5d ago

I've heard it said, that if the planes had hit in the lower floors, that might have happened.

I've also heard that the only people who got out of the towers were on floors below where the planes crashed.

A lower floor strike would have killed a lot more people either way.

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u/Practical-Pickle-529 5d ago

A handful of people in the second tower escaped that were above it. Not a soul in the first. 

Also I think hitting super low would be impossible because of the surrounding buildings 

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u/Hoppie1064 5d ago edited 5d ago

I'm thinking it was because of piss poor student pilots. The towers were right on the Hudson. A wide part near the bay. Nothing between them and the bay except Battery park and a few comparatively short buildings.

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u/Practical-Pickle-529 5d ago

That’s a good point. That’s probably the reason, rudimentary ass pilots. I can’t imagine how devastating it would’ve been if they hit lower. I read so many stories about the people in tower one/windows on the world restaurant who were trapped. So sad. 

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u/FuegoHernandez 4d ago

Imagine if they hit the towers an hour later. Most people were still not at work yet, and the observation deck for tourists was not open yet. 2000+ more people could have died.

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u/Practical-Pickle-529 4d ago

Yep. I think this is more evidence that the WTC was the distraction/secondary targets. Despite being the absolute worst tragedy of the day, by far, it will always surprise me that only ~2900 people were killed in NY. 

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u/Everestkid 4d ago

One of the people thought to be the organizers of 9/11 said Flight 93's target was the Capitol building.

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u/uss_salmon 4d ago

Tbh that one probably would have had the least casualties had it happened. It’s a relatively flat building and like the pentagon most damage would probably be limited to the immediate impact area.

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u/frontadmiral 4d ago

That and they were hauling ass. Not a ton of time to adjust for positioning when you’re going that fast as an inexperienced pilot.

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u/HallandOates1 4d ago

I watched a doc awhile back where people on the higher floors and any floors in the second tower said their bosses were telling them go back to work and to not leave. I would've been like gmtfohn!

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u/Stop_icant 4d ago

People in tower 2 were told to stay put by the port authority after the first plane hit so that it was easier to manage the evacuation and rescue effort in tower 1.

Luckily for thousands of Morgan Stanley employees in tower 2, their independent security guy was like fuck that and got his people out despite instructions to stay put.

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u/ckdblueshark 4d ago

Rick Rescorla. Amazing life story, including service in the Vietnam War (he's the guy in the cover photo of the book We Were Soldiers Once... And Young), teaching, and then his career in corporate security.

After the 1993 bombing, he argued for moving the company offices elsewhere but the lease wasn't up until 2006. He then did what we could, including holding surprise evacuation drills that he would time with his stopwatch.

On that day, he got most of his people out and died trying to get everyone out -- he was last seen heading upstairs.

Of ~2,700 employees, 13 died. Rescorla, two of his deputies, and a security guard were among them as all four had stayed behind to save others.

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u/grumpybadger456 4d ago

In some of the documentaries there is audio from 911 where they advised people to stay put. I think they also told people (from below the crash zone) who got down to the lobby to go back to their offices, where a lot did - which made it a lot harder than just evacuating both buildings from the first crash. I know we are looking back now with hindsight about what happened with the second crash, and the buildings falling, none of which was anticipated, and none of which the first responders were trained to deal with, but so heartbreaking to watch the footage.

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u/gopiballava 4d ago

My MIL was working in one of the tallest buildings in Pittsburgh on 9/11. After the second plane hit in NYC she told her boss that they should probably leave. Her boss was like “nah, you can go if you really want but we’re fine.” Just as my MIL was going, someone higher up decided to send everyone home.

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u/AlmondCigar 4d ago

I guess a lot of the people in the twin towers had bosses just like your MIL.

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u/SOTG_Duncan_Idaho 4d ago

The towers, like all megastructures, are carefully designed to fail as gracefully as possible. Specifically because it is entirely unacceptable for a high rise to topple.

Doesn't mean it can't happen and there are limits to what they can do, but they do a lot of work to ensure that if the structure is going to fail, it's not going to topple.

This is one reason all the bullshit conspiracy theories about how the collapse was a controlled demolition are bullshit. The engineers who built those towers did not build them to withstand what happened to them, but they did a good job making sure that even worse would not happen. The structure performed exactly as you want them too if collapse is inevitable. That is, they collapsed on their own footprint.

It's like when someone cuts down a tree. You cut a notch so that when the structure of the tree fails, it fails the way you want it to. Except, it's a lot more complicated with a 100 story building.

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u/FuegoHernandez 4d ago

I think it’s amazing they stood for as long as they did. Engineers build a hell of a structure to withstand the initial impact of a commercial airliner slamming into it at 500 mph FULL of fuel. I think people forget these planes were east to west coast flights that were carrying a shit load of jet fuel.

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u/damnedifyoudo_throw 5d ago

One of the early ideas had been to knock one tower into the other.

The science of “pancaking,” which is ultimately what happened (structure weakening and putting pressure below it, increasing weight until the whole thing fell straight down) was basically unknown and unanticipated. The logic of sending firefighters was that they might be able to control the blaze and save people.

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u/JeruTz 4d ago

One of the early ideas had been to knock one tower into the other.

I think that was the intended goal of the '93 bombing attack. Destroy the foundations in the right place and cause one to fall over into the other. Fortunately that never came close to happening.

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u/quantum1eeps 4d ago

Yes, it’s been seen and studied since but not observed previously to 9/11 (progressive collapse by fire)

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u/Cayowin 4d ago

From the 911 report:

There are several points that should be made. First, the building is not solid; it is 95 percent air and, hence, can implode onto itself. Second, there is no lateral load, even the impact of a speeding aircraft, which is sufficient to move the center of gravity one hundred feet to the side such that it is not within the base footprint of the structure. Third, given the near free-fall collapse, there was insufficient time for portions to attain significant lateral velocity. To summarize all of these points, a 500,000 t structure has too much inertia to fall in any direction other than nearly straight down.

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u/Kevin91581M 5d ago

I was thinking along similar lines as I was watching the coverage

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u/MoreGaghPlease 5d ago

So we actually have a told answer to this both from tapes of Bin Laden found in Afghanistan early in the war and from evidence given by KSM when he was being tortured by the CIA.

Bin Laden did not expect the towers to collapse, and they were secondary targets. The main targets were the White House and the Pentagon, and he believed that both would be destroyed if the planes hit their target (obviously the Pentagon was only damaged, probably they did not appreciate how big it is). But they did not expect the towers to collapse. They had no knowledge or understanding of the engineering of the towers, they believed that it was likely to cause a fire and maybe kill the people above the impact. But they also didn’t care very much or really think about this aspect of it, it was more like something that they just mused about.

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u/bouncypinata 5d ago

the last target was the capitol. It was Congress' first day back in session.

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u/damnedifyoudo_throw 5d ago

The Capitol is the assumed target in the book The Only Plane in the Sky.

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u/Patsfan618 5d ago

I'd imagine it could've been either. Which ever they could target the easiest. They didn't really plan on doing any go-arounds, so whatever they could hit, is what they would. 

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u/ShockAndAwe415 5d ago

Whatever the target was, a salute to the passengers fo Flight 93. Let's Roll.

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u/graceful_mango 4d ago

My grandfather is buried a few rows away from one of those passengers and even now his (flight 93 passenger) grave has flags and flowers at it constantly.

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u/sozcaps 4d ago

Let's Roll

Draxx them sklounst.

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u/Yarnprincess614 4d ago edited 4d ago

My cousin went to the same college as Todd Beamer(the let’s roll guy). Their student center is named after him.

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u/gsfgf 5d ago

Yea. I think the Pentagon was plan B for both flights since they knew it was a physically larger target. You don't get to swing around for a second pass at DC. Plus it's south of DC proper.

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u/Felaguin 4d ago

Not just larger but the Pentagon was built in an era when everything was massive concrete and steel. It wasn’t designed to be a fort but the walls are THICK. Cell phones don’t work well inside because of all the concrete and steel.

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u/splittestguy 4d ago

No, The pentagon was a primary target. There was another plane that crashed in PA, destined for the White House.

The plane was nearly an hour late that day, meaning the passengers had learned of the terrorist attack happening in NYC. So when the hijackers killed a passenger and tried to gain control of the cockpit. The passengers fought back. During the struggle, the plane nosedived into a field in PA.

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u/DClawsareweirdasf 4d ago

My understanding, and I could be wrong, is that the hijackers actually did gain control and lock themselves in the cockpit.

But the passengers did begin to fight back and the pilots intentionally took it to a nosedive.

Again, I could be wrong but this is my memory of the various documentaries and news I’ve seen.

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u/Pr0phetofr3gret 4d ago

The black box audio supports that they did. The terrorist realized they would not maintain control for much longer as the passengers fought for entry and chose to put it down in the field instead.

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u/elephant35e 4d ago

Whichever they could target the easiest

That would be the Capitol. The White House would be too hard to hit due to the buildings surrounding it.

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u/say592 4d ago

Loss of most of Congress would be far more chaotic too. We have a succession plan for the President dying in office, it's even happened a few times. We have a protocol for Congress people dying too, but it's never been tested on that scale and there would be no immediate or instant succession. Of course I don't know if they knew enough about American civics to understand that, they probably just saw a packed building with a lot of soft targets.

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u/7hought 4d ago

If they hit the capitol, they’d get a few, but congresspeople have their offices in buildings close to, but not in, the capitol building. It’s maybe 6 different buildings or so. Ironically they would have been better suited targeting one of those if they wanted to cause fatalities among politicians.

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u/Ok-Cartographer1745 4d ago

Allegedly, they were attacking the three main symbols of the US.  Finance (twin towers), military (Pentagon), and presidency (white house). Basically the idea was that nothing was safe - the military, the banks, and the very leader of the country. 

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u/alliesto 4d ago edited 3d ago

The World Trade Center buildings were also iconic to the New York skyline, and further New York City is iconic itself. I’m not sure how relevant this is, but at one time the World Trade Center buildings were the tallest in the world so maybe that played into it as well.

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u/DuplexFields only uses old.reddit 4d ago

Imagine if it had been the first target, before warnings went out. The world would be a very different place.

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u/whanch 4d ago

Probably not, the president wasn't even there. He was in a school in Florida

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u/BearMeatFiesta 5d ago

Part of the reason that the pentagon did not sustain more damage is because the section the plane hit had recently been renovated. If the plane had hit a section of the pentagon it would have done way more damage.

Source my father was working at the pentagon when the plane hit. I worked at the pentagon several years later (about 8 years later) and have gone to the sector that was hit. There is a chapel and a memorial in that sector now. Very pretty, didn't see it get used much.

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u/EmperorUtopi 5d ago edited 4d ago

Interesting tidbit of info, adding onto what u said, apparently they were renovating steel reinforcement to boost protection in the Pentagon. And coincidentally, the side the plane HAPPENED to hit was the ONE dang side being reinforced with steel support at the time. And on top of the strongest side being hit, hardly anyone was in that quintant of the Pentagon since it was under renovation, drastically lowering casualty count. (800 out of the usual 4000 present, 189 of those 800 killed).

I heard this somewhere so u can fact check me, but if that’s the case, its so cool

Edit: https://www.hirschsecure.com/resources/blog/the-worlds-most-secure-buildings-the-pentagon Okay the info is real! Additional info, they were adding new sprinkler systems in that one section of the Pentagon which contained the fire, and ALSO blast resistant windows.

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u/John_Tacos 5d ago

And it had literally just been finished, so very few people had moved back in.

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u/BlottomanTurk 4d ago

Iirc, the structural construction was finished, but the interior spaces were still being worked on.

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u/Revcondor 4d ago

A worker is in the pentagon, puts the finishing touches on on a huge renovation.

Stands there and appreciates his hard work

Suddenly a plane comes crashing through the wall he just finished destroying all of his hard work

Stands up and dusts himself off, looks at the damage and says “Aw shit, I bet nobody’s having a worse day than me right now!”

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u/Master_JBT 4d ago

narrator: he was wrong

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u/k_manweiss 4d ago

Nah, that worker would be thrilled. Work was complete, payment would be made, and now they need someone to do it all again. That's a bonus.

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u/TheShadowKick 4d ago

His boss might be thrilled. The worker would be pissed.

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u/ashcaps 5d ago

Yeah, I had an old teacher who was stationed at the Pentagon and was stuck in a crappy temporary setup while the renovations were being done. If they had gone any faster he’d be a dead man.

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u/[deleted] 5d ago edited 5d ago

[deleted]

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u/RainaElf 5d ago

this is the part people fail to consider.

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u/Prestigious-Flower54 5d ago

This is actually part of what fueled the inside job conspiracy. People found it too convenient the plan hit a section that was being renovated.

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u/oisiiuso 5d ago

dumbasses act like it was so improbable and not a one in five chance.

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u/admalledd 5d ago

FWIW, supposedly the "which side first to renovate" included some risk calculations on which side was at most danger, so that played into which one first. My memory on the reports was that some other section was more in danger, but too hard to move at the time/not worth it vs this other slice to do first.

So like, still a chance, but better than a one-in-five.

Note: the actual risk assessments were(are still?), of course, classified/redacted, so this counter-claim just spread MORE fuel to the nutjobs when the investigations/reports came out.

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u/Jolly-Sock-2908 4d ago

IIRC the renos with the steel reinforcements were done in response to the Oklahoma City bombing. On the images on TV, the side that was hit was closest to a highway, so it would make sense if that side was the most vulnerable.

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u/oisiiuso 4d ago

good insight!

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u/ShouldersofGiants100 5d ago

dumbasses act like it was so improbable and not a one in five chance.

Less than one in five.

The Pentagon has a large parking lot that is then immediately next to a raised highway. It would be incredibly difficult to hit either of the southern sides as a result (especially if you're a pilot operating the plane for the only time, at max speed and you get one shot). From where they were flying, it was literally the only side they could target.

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u/gsfgf 5d ago

Though, I think the fortification program was anticipating a truck bomb not a plane. Luckily, they started with the sector a plane would line up on.

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u/c_the_potts 5d ago

And there are a bunch of high-rises just south of the highway too which doesn’t help either

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u/grandoz039 4d ago

You mean more than one in five, right?

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u/ShouldersofGiants100 4d ago

Yeah, that one was a misspeak.

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u/unrebigulator 4d ago

It would also be a conspiracy if it hit a side that was NOT being renovated.

tHe hIjACkeRs knEw whICh WaLL tO hit! and so on.

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u/Prestigious-Flower54 4d ago

That's part of the explanation for the white house, they knew to shoot down a commercial airliner. Ignoring the fact that anything flying near the White House is not supposed to be there.

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u/ermagerditssuperman 4d ago

Yeah, last year when a pilot went unconscious and their plane auto-piloted through DC airspace, the reaction was immediate and severe - a fighter jet went to intercept and caused a sonic boom that was heard throughout most of Northern Virginia. DC airspace is taken seriously.

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u/Yog-Sothawethome 5d ago

I mean, a 1 in 5 chance chance is still pretty high all things considered. Probably higher if you take into account that the plane would be coming from a certain direction depending on where it took off and a hijacker probably wouldn't decide to circle around the back.

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u/TimeTravelingTiddy 5d ago

It would have done more damage but they were never taking more than 1 side with 1 plane

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u/TonicSitan 5d ago

It's amazing to me that Bin Laden didn't even really seem to grasp the most consequential part of his own plan: Mass media recording

The plan was for all of these attacks to occur near simultaneously, within 15 minutes or so of each other. But the fact that they didn't is probably the most significant part of the event. Instead of just hearing about a bunch of things happening all at once, the world got to absorb each separate strike one after the other.

The day starts in confusion, as the first plane hits the tower. Nobody is sure whether it's an accident, intentional, or what, if anything, is next.

15 minutes later, the second plane hits on live international television and removes all doubt. This is coordinated. This is an attack. Panic begins.

30 minutes later, the Pentagon is hit, and now, terror completely takes hold. It's now a multi-location event. Anything could happen, from anywhere. Closings and evacuations start en masse, not just in America, but around the world.

The 4th plane crash really is the end of serenity. It would have undoubtedly been a bigger deal if it had reached it's target, but even in the most remote areas, there is no solace to be found. The goal of terror has been achieved.

9/11 would still be a massively important historical event even if everything had gone to plan. But the fact that we have recordings of the plane crash, people jumping, the collapses, is more visceral and terrifying than Bin Laden could have dreamed possible.

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u/QuantumG 5d ago

The footage itself became a weapon, amplifying the fear beyond anything physical that day. Every replay, every broadcast of the planes hitting, every image of people running covered in dust, seared the moment into global consciousness. This wasn't just an attack on physical structures—it was an attack on the psyche of a generation. The media, in its endless loop of tragedy, ensured that the horror lingered, lived on, and reshaped the world in ways even Bin Laden couldn't have fully calculated.

What he didn't anticipate was the sheer power of the human narrative, especially when visualized in real-time. The world didn't just hear about 9/11; it witnessed it. The story wasn't told after the fact but unfolded in front of the eyes of millions. It wasn’t just history—it became the defining moment of a new era, one where terror was no longer something you heard about from faraway lands but something you saw, felt, and feared could happen anywhere.

The legacy of that day wasn't just in the buildings lost or lives taken, but in the way it forever changed how we experienced fear, conflict, and the omnipresence of media. Bin Laden may have lit the fuse, but it was the media that ensured the explosion reverberated for decades to come.

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u/MonsieurLeDrole 4d ago

This can't be overstated. Like that day, the vast majority of people watched the same horrifying TV show all day, and it was this mass psychological event. If you look ahead in history at other terrorist attacks, like the Boston Bombing, the reaction is way more fractionalized. Instead of everyone going to the TV for information, people went to the Internet. And because of social media, instead of this massive one way conversation, we had all these people communicating online. That's profoundly different.

The broad social and political reaction to 9/11 would have been completely different had it happened in 2011 instead of 2001. Yes we had the Internet then, but online video was sparse and social media wasn't really a thing, so it really was the last biggest tv event ever. The next day, talking to friends, everyone had watched the same thing. But since there wasn't much way to communicate back, we were all waiting for.... for TV to say more or something else.

Like thinking back, I remember trying to call my family that was in NY, and I called my GF, and called a friend to hangout and drink and watch and lament, but I don't think we even used the Internet that day, not even to play counterstrike, and certainly not to contact friends. Didn't send a text message either. That seems unthinkable now. Anything happens, and first thing you do is go online. It's a different world.

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u/SteamboatMcGee 4d ago

That's a good reminder. I had family in the Pentagon, and we eventually found out they were ok that evening through a family phone tree.

When's the last time you needed info spread and a phone tree was the optimal method?!

But there was no social media, the Internet of the time wasn't useful for this, and phone circuits were overwhelmed in all the affected areas and stretched thin everywhere. It was a different era.

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u/Jalvas7 4d ago

Very well said.

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u/millerlit 5d ago

On 60 minutes they did a story with the NYFD.  They believed the towers would not fall due to their never was a case of a skyscraper coming down from fire up until that time.

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u/sangaremuso 4d ago

Sigh. That's hard to hear. And I wonder whether they would have let so many emergency personnel in to aid those in the towers if they were calculating for a possible collapse. (I have no idea). Either way, I'm humbled by their sacrifice.

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u/travelingwhilestupid 4d ago

I presume they stopped sending personnel into the second tower when the first tower collapsed...

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u/Backwoods_Barbie 4d ago edited 4d ago

But there wasn't just a fire, planes also crashed into them. Which is a huge lateral impact load and my understanding is the exterior steel columns were designed to handle some of the loads, so cutting some of them in half compromises the whole building. Maybe a building with all interior supports and a non-bearing curtain wall facade would fare better. 

I think people just have a hard time imagining such significant buildings failing so catastrophically, leading to overconfidence in their integrity. I wonder how they differently they would have handled things if they considered collapse a serious threat. 

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u/Bacong 4d ago

the main reason they collapsed was the fires weakening the perimeter columns, causing the floors to buckle which caused the buildings to collapse on themselves.

jet impact certainly did not help however.

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u/UglyInThMorning 4d ago

On top of the structural damage, the impact also blew off a tremendous amount of the fireproofing. There was a worse fire damaging material that had already been compromised, it was a lot of impact related stuff compounding.

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u/I-Am-Uncreative 4d ago

To be honest, the buildings DID withstand the impact for quite a while, which when you think about it is pretty impressive. Obviously they weren't invulnerable, but they were designed well.

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u/Ok-Cartographer1745 4d ago

As a former New Yorker - not that I really care, but just for giggles' sake: it's actually the FDNY. They don't call themselves the NYFD. 

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u/ritergrl 4d ago

I can tell you that my best friend, born and raised in New York, assured me that day several times those towers would not fall. There had been a previous bomb set off in one near the ground, and nothing happened. She was convinced, like many, that they could withstand everything.

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u/sboaman68 5d ago

My grandpa was an engineer on the twin towers when they were built. My mom was talking to him on the phone after they were hit. He assured her that there was no way those towers were going to come down while they both watched the news. When the first tower collapsed, my mom said he started to get some emotion in his voice(very rare for him to show emotion of any kind) and quickly ended the call. As far as I know, he never talked about what happened to anyone I knew after that.

I also highly doubt the terrorists knew they would come down. They just struck them for the symbolism.

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u/mmats01 4d ago

If the people that built them didn't think they were going to come down there's no way the terrorists would have known.

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u/HillarysFloppyChode 4d ago

The structural engineer who made them had engineered them to withstand a 707 (the largest plane available at the time).

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u/TheMuon 4d ago

There's also a difference between a lost plane in the fog trying to land and a hijacked plane going full send into the building.

The former is slower and loaded with less fuel.

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u/Marquar234 4d ago

Also, it was most likely that an accidental collision would be from a landing aircraft which would mean a lot less fuel on board. IMS, both WTC aircraft were "heavy", meaning a larger fuel load for cross-country flights.

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u/moonbunnychan 4d ago

There's a History Channel doc about the WTC where they were interviewing one of the designers and he talks about how they built it to be able to survive a plane crash. But it was designed to sustain the damage of a much smaller plane, not a giant jet.

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u/FlowJock 5d ago

This.
I remember hearing that they were pleasantly surprised.

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u/Squigglepig52 5d ago

I always imagined Bin Laden thinking "Oh, fuck. that's gonna cost me later."

I didn't realize they were the secondary targets.

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u/Gekreuzte_Gewehre 5d ago

Actually, yeah, you're pretty close. Bin Laden said they didn't in their wildest dreams believethe towers would collapse and then on top of that......we have radio intercepts in Tora Bora......"I'm so sorry, my brothers, that I've brought this upon our heads!" Bin Laden himself said this as B-52s pummeled the hell out them.......

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u/GTOdriver04 5d ago

I’ve always wondered if bin Laden considered how pissed the US would be, and that they wouldn’t stop until they killed him.

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u/Whiterabbit-- 5d ago

He probably was surprised that he lived so long afterwards.

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u/John_EightThirtyTwo 5d ago

He was hunted into a hole and stayed there, with his head down, for the rest of his life, until the U.S. came and killed him. I'm sure from his point of view it was all worthwhile, given how successful he was a goading the U.S. into a self-destructive spasm of pointless violence. He played us like a fiddle.

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u/munchkinatlaw 4d ago edited 4d ago

He was living in a large house with three wives, two an adult son, a bunch of kids and grand kids, satellite TV and a shitload of porn. It wasn't even a bad existence, especially compared to living in Tora Bora.

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u/SchismZero 5d ago

Wow, that's actually an interesting factoid that the towers were not the primary targets. Because of the result of the attacks, we talk about the world trade center a lot more than the pentagon or the White House when referencing 9/11.

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u/Ambitious_Toe_4357 5d ago

Weird, considering the WTC bombing in 1993 by Al Queda intended to cause the North Tower to collapse into the South Tower. Would you need some knowledge of the architecture to know the best place to set the bomb? I guess this was only because it was a soft target that represented US economic power. With planes the other targets came into range.

Would the towers have been repairable after they were hit by the planes. Would they have to be demolished because they would be unsafe? I'm sure in the case of the WTC and terrorism, no expense would be spared to repair the damage.

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u/ShouldersofGiants100 4d ago

Weird, considering the WTC bombing in 1993 by Al Queda intended to cause the North Tower to collapse into the South Tower. Would you need some knowledge of the architecture to know the best place to set the bomb?

This reminds me to a degree of how the Columbine shooters thought their propane bombs (which utterly failed) would drop the library onto the cafeteria and kill hundreds.

My assumption is that they just assumed that, if they built a big bomb, the rest would just happen. Frankly, I don't think there is any scenario where the North Tower collapses onto the South. The fact is, the weight of the building pushing down is going to be so much greater than the slight tilt if it fails asymmetrically that there just isn't a way to topple the building. Especially considering the WTC were built with a structure that put most of the support in the centre, not on the edges, so it's not like there would be much-lopsided damage to the main supports anyways.

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u/Christmas2025 5d ago

100% no—everyone was incredibly surprised that day when they did.

If the hijackers had anticipated the physics of what would’ve happened, they would’ve hit the buildings as low as possible and after 9:00 AM, as this would’ve resulted in tens of thousands of more deaths. In the North Tower (the first hit), no one above the floor where the airplane impacted survived, as all the staircases were severed. If Atta had hit a lower floor and after 9:00 AM (instead of 8:45 AM), tens of thousands more would’ve assuredly died from that tower alone, and the tower also would’ve collapsed much sooner, and potentially toppled over, which would’ve caused even more deaths below.

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u/John_Walker 5d ago

While obviously, trapping more people would have resulted in greater deaths, but the plane that hit the south tower hit on the level that had the sky lobby with the elevators that took people to the ground. It had hundreds of people crammed in there trying to evacuate after the north tower had been hit.

That was one of the worst places it could have hit. The only saving grace was that the angle it hit at left one of the staircases intact, allowing 18 people to escape from at or above the impact zone.

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u/P3for2 5d ago

Where they hit was a lucky break for them. It hadn't been deliberate. They weren't very good pilots.

But a while ago I was watching a documentary on the 9/11 attack. I don't remember which tower (I have trouble remembering what happened where), probably the one you're talking about, but there were trapped people, because the staircases and elevators were taken out of service by the plane crash. And there was audio recordings of firefighters making it up to the floor where they were trapped at. And you can just imagine the elation they all felt when they realized if someone came up, that meant there was a way down. But the entire time this documentary was running, there was a countdown timer in the corner until the building collapses. And it was not long after when the firefighters made it up to those trapped people that the countdown ran out of time. That was so heartbreaking.

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u/John_Walker 5d ago

I’d like to see that. It had to be south tower, the north tower had all of its staircases severed. Not a single person from at or above the impact zone survived in the north tower.

The man in the red bandana is another 9/11 legend. You could be thinking about him maybe.

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u/P3for2 5d ago

Yeah, I just looked it up, it was the south tower. Sorry, can't remember which documentary it was.

It was firefighter chief Orio Palmer's audio recording. I do know of Welles Crowther, but this was the FDNY.

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u/_munkee_ 5d ago edited 4d ago

Actually in 1993 they drove a van of explosives under the WTC and tried to blow up a pillar. Someone wanted to bring the towers down.

1993 WTC bombing

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u/P3for2 5d ago

The WTC has a lot of history of getting attacked. This is why when the first plane hit the first tower, I thought it was a bomb (I hadn't seen the plane). And to be honest, I didn't pay much attention, not until that second plane hit.

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u/GTOdriver04 5d ago

My mom’s first reaction to hearing the news was “so, they finally got them.”

I later read up about how they had tried before and failed. My mom was upset, as were we all, but she wasn’t surprised that they tried again.

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u/Tim-oBedlam 5d ago

I had a friend in NYC who grimly commented the evening of 9/11 "they sent the varsity terrorists for this one. The '93 bombing was the JV squad."

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u/concernedindianguy 4d ago

Not American. What’s a JV squad?

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u/undisclozed 4d ago

Junior varsity. In high school sports varsity is the main team and junior varsity is a secondary team made up of people not good enough to make the main team. Calling something JV is usually used here as an insult to imply that that someone sucks at what theyre doing.

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u/Tim-oBedlam 4d ago

Exactly what I meant. One of the '93 terrorists was arrested because he reported the van stolen and tried to reclaim the damage deposit (they'd rented a van, filled it with explosives, and driven it into the basement of the WTC in an attempt to collapse the whole building; 6 people were killed and hundreds injured).

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u/UnicornFarts1111 5d ago

My sister said my mom called and woke her up after the first plane hit and said "we are under attack" and then she saw the second plane hit.

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u/AffectionateMoose518 4d ago

It's still kinda crazy to me how nobody really did that much to prevent future attacks after the 93 bombing. But then again, things don't often get done well or at all until there's proof it's absolutely necessary, and since the bombing didn't end up doing much whatsoever, but the planes crashing into the towers did, I suppose it was the wakeup call to be more cautious and much safer with things like that

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u/Slut_Abuser_69 4d ago

In 1993 we weren’t living in an “age of terror” yet, and it was still part of the culture here in NY to take shit like that in stride. 9/11 actually changed the city on a cultural level

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u/purepersistence 5d ago

I was focused on my job trying to debug a tough software bug. Frankly I was a little irritated about all the news at the office and wanted people to just shut the fuck up. Then the 2nd plane hit.

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u/csonnich 5d ago

I was about to go study for my chemistry exam, but when the second plane hit, we figured it would be postponed.

We were wrong. 

That professor was really great outside that one incident. 

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u/P3for2 5d ago

Wow, surprised. It felt like the whole world shut down. It was soooo quiet. Businesses and classes here were closed for like a week, on top of, of course, the airports shutting down too. It was so strange not to hear airplanes flying overhead (we're near a major airport).

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u/csonnich 5d ago

We were definitely not closed for a week. I don't remember very well, but I'm pretty sure I was in classes again the next day.

I went to school in a small town, though, so I think they figured we weren't much of a target. 

My dad did get sent home from his job at an oil refinery for a few days, though. 

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u/Christmas2025 5d ago

Exactly, and I think the fact that the 1993 bombing didn’t bring them down is what further cemented people’s belief by 2001 that it couldn’t be brought down as easily as may have been thought before 1993.

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u/CougarWithDowns 5d ago

They picked earlier flight so they would have less passengers to deal with. If they hit them after 9:00 a.m. they would have got on a later flight and had to deal with more passengers. Reduces the chances of their mission

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u/Nickppapagiorgio 5d ago

they would’ve hit the buildings as low as possible and after 9:00 AM, as this would’ve resulted in tens of thousands of more deaths.

I don't think the time would have changed. If they were going for maximum number of deaths, they would have hit later, regardless of whether they thought the towers would come down or not.

They were going for maximum global audience, not maximum number of deaths. The 8 o'clock hour(AM) in New York City is probably the hour with the most human beings awake on Earth at any one time. All of Europe and Africa was in the middle of the day. Most of Asia would be awake too. It would have been 8 PM in China, and 9 PM in Japan. In South America, it would have been 7 AM to 10 AM. The only areas that were in the middle of the night were remote stretches of the Pacific.

If you start bumping it to later in the day in NYC, you begin to lose the live Asian audience as the Chinese, Japanese, and Indians begin to go to sleep, and they represent about 4 out of 10 humans. This was about publicity for Al-Qaeda, and that time of day was maximum publicity.

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u/Goodgoditsgrowing 5d ago

(All the below feels insensitive to write, so please don’t read if you were impacted more than indirectly by the attacks. As someone who had no direct connection and only experienced it as increased security at airports and societal changes I was too young to understand, I have a different relationship with 9/11 that I admit is grossly callous and not appreciating the trauma so many went through, but I do not intend to cause anyone harm by talking out my ass)

Interesting, I’d never thought about it in those terms. Makes you wonder if the architects of the attack were a bit freaked out when they realized what they’d actually accomplished. Sure, a true believer would be happy and see it as a sign from god that hod was happy with the attack, but every organization has people just there for a paycheck - and they must’ve been shitting bricks after it collapsed and they realized their intended or stunt had a much higher death toll than they thought they’d get.

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u/bernardobrito 5d ago

<<<They were going for maximum global audience, not maximum number of deaths. >>>

As I understand it, the early morning was chosen because of logistical reasons. Early morning flights are more reliable (fewest delays /cancellations) and they could get all the hijackers aboard.

It had to be coordinated and surprise. Same reason why Bojinka was simultaneous.

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u/John_Walker 5d ago

The point about the timing is legit. Flight 93 was delayed and that delay allowed the passengers to find out about the other planes before it was too late.

They needed all the planes to leave within minutes of each other to pull it off. They probably expected to be shot down if one of the planes was too late getting going.

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u/Minute_Cold_6671 5d ago

They also wanted flights with fewer people to lessen the chance of being overpowered and stopped. The timing was for the reasons above and those flights being closer to half booked.

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u/P3for2 5d ago

No, those involved in the planning of the attack were all extremists. They weren't there just for a paycheck. They were willing to die for their cause.

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u/RegretsZ 5d ago

I read (albeit, on Wikipedia) that the 'muscle' hijackers were not aware it was a suicide missision, only the Pilots did.

If this is accurate, my question is: what did they think was gonna happen?

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u/nishagunazad 5d ago

That theyd get the plane to a country willing to give them asylum, or at least make a stand for the cause. Prior to 9/11, plane hijackings were largely nonlethal affairs. You either got the plane to where you could take refuge or you got into a stand off where you would either be killed or captured, but you had a much better chance at survival than you did yeeting a plane into a building.

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u/WaitForItTheMongols 5d ago

Hijackings were relatively common in the late 1900s. The difference is that the consequence of one was almost always just that the plane/passengers were being held for ransom. This actually contributed to why 9/11 was so "easy" and why it could never happen again. When the passengers found out they were being hijacked, their thought was "oh jeez, I'm going to be delayed getting where I'm going because they're going to have to negotiate getting their ransom payout" rather than "the vehicle I am in is about to be used as a weapon". If anyone tried a hijacking today, they would find that the passengers are much more ready to fight back, and they would have much more trouble.

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u/gopiballava 4d ago

Exactly. I remember thinking about what I would do if my plane was hijacked in the 1990s. Don’t get noticed. Don’t make a scene. Don’t make them think you might be law enforcement etc. They has threatened and murdered hostages before, but it was one at a time usually.

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u/Micbunny323 4d ago edited 4d ago

In addition, airline protocol was for pilots to surrender the cockpit to hijackers, so as to minimize conflict and ensure the lives and security of the crew and passengers. Better to let the ransom takers take their ransom and delay the plane a bit then make them do something drastic to get what they want.

9/11 changed a lot of things, but airline protocols for hijacking and cockpit security were one of the biggest. Before then it wasn’t uncommon to see the cockpits open during initial boarding, and even be allowed to duck in by the crew to “get a view of the cockpit”. I remember doing this when I was younger, parents would/could often take their kid in to view the pilots working during the preflight check. I cannot imagine a random passenger being allowed in there anymore.

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u/Equal-Temporary-1326 5d ago

It was a suicide mission, so none of the hijackers were getting paid to do it.

They were all just brainwashed religious extremists.

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u/BullyFU 5d ago

They were paid before the attack. There's video and eye witness testimony of the hijackers living it up shortly before the attacks.

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u/dwightsrus 5d ago

Not in India. I remember it was daylight because it was still 6:15 PM in India when the first place hit. People don't go to bed until much after 10 PM.

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u/SenatorStone 5d ago

Sorry but why is this being upvoted? If this is your personal speculation then maybe you could clarify that. If the timing of the attack was dictated to attract the most attention then why did Bin Laden/ Al Qaeda initially deny responsibility for the attacks?

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u/damnedifyoudo_throw 5d ago

I highly recommend the book The Only Plane in the Sky for people interested in this. Goes over the strategy of the rescue which assumed the towers would stay standing.

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u/TerribleAttitude 5d ago

The original WTC attack in 1993 apparently was intended to knock one tower over completely into the other. Obviously that didn’t happen. No building of that size had ever intentionally or unintentionally come down before 9/11 so no one knew for sure exactly what would happen. So my thought is that they didn’t know or expect the towers to collapse in 2001, but did think it was possible.

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u/Eric848448 5d ago

intentionally

What exactly is the demolition plan for a building that big when it’s past its useful lifetime? Surely it’s too big for a controlled implosion.

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u/Tough_Dish_4485 5d ago edited 5d ago

Tall skyscrapers closely surrounded by other tall buildings are dismantled piece by piece.  This takes awhile and is expensive, but the only way to demolish buildings in high density areas without damaging others. This is what was done to the Deutsche Bank Building which was heavily damaged on 9/11 by part of the World Trade Center tower collapsing into it.  

Other notable dismantled skyscrapers include the Signer Building in NYC and One Meridian Plaza in Philadelphia.

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u/miteymiteymite 4d ago

Yeah, it took YEARS to dismantle the DB building.

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u/2Dprinter 5d ago

As others have noted: no, they didn’t. I will add, as someone who was in lower Manhattan at the time, that nobody in the public expected them to either.

If that had been the expectation, police and fire crews would have begun cordoning off and evacuating the areas surrounding the towers. Businesses and residents would have left their premises. College classes weren't even canceled.

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u/softt0ast 5d ago

My students and I watch a news reporter showing the towers fall for 9/11 this year (they've never really watched anything OTHER than the planes hitting), and we had to talk about why the guy was so close. It seemed so obvious to them the towers would fall, but it's was hard to explain thay we thought they wouldn't. Almost like a modern day Titanic.

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u/_j7b 4d ago

Mount Vesuvius was thought to be a mountain. The Roman’s didn’t have a word for volcano.

Sometimes we just don’t know what we don’t know. It’s wild to see an example of this in my lifetime.

IIRC, a documentary did say that the unique structure of the WTCs was part of the reason why it collapsed. Ironically, and supposedly, the architect designed it that way to help his own fear of tall buildings. IIRC, it was like an exoskeleton rather than having all its support come from a strong core.

In fairness, you smash a few planes into any building I’d expect most to come tumbling to some degree. Then again, I’m Australian. Our buildings fall down without much prompting.

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u/ActUpEighty 4d ago

The towers' collapse was such a surprise that a large portion of the world still cannot accept their collapse was the result of planes being flown into them.

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u/fryguy850 4d ago

Or not being flown into them like building 7

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u/stogie-bear 4d ago

Hi, former architect here. This is not something you plan for, and there was really no precedent for it because:

  1. There aren’t many skyscrapers out there like the WTC towers. The superstructure was a tube of columns and the floor plates were supported at the perimeter. The failure was in the connection between the floor plates and the columns, and when one plate failed it took down the already weakened one below. Then the weight of multiple plates caused the cascade failure. That's not what you’ll expect or plan for without 20/20 hindsight and before this there were no instances of buildings failing like this. 

  2. Before this attack, “what would happen if you put a huge jet fuel fire in there” just isn’t something you would have asked when designing a skyscraper. 

So I don’t think anyone would have planned for the particular way the structure failed, including the terrorists. I think they wanted to cause a lot of chaos, death and destruction. I don’t think they planned on the particular type of destruction they caused. 

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u/hueylouisdewey 4d ago

The unprecedented nature of the event is very relevant. OP says no building like it had collapsed from fire before, but also no building had a fricking aeroplane fly right into it! I'm no architect or engineer and I don't know the exact causes of the collapse but this feels important.

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u/Dry_Car2054 4d ago

The Empire State Building had a B-25 bomber fly into it. It did some damage but didn't cause a collapse. The architects for the WTC designed for that to happen again since it was a known possibility. They didn't anticipate a plane that large with that much fuel. Also, there had never been a skyscraper lost to that kind of fire so that wasn't thought to be possible. After all, it was concrete and steel and therefore not flammable. The hijackers picked planes going to the west coast that were full of fuel. That made for a fire that was able to do structural damage that led to the collapse.

Edit: spelling.

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u/uptownglitterbomb 4d ago

Can’t answer the question posted, but very related and it still gives me chills: I was working on my masters in architecture on 9/11. I was sitting in an advanced structural physics class when the first plane hit the tower, hundreds of miles away. Someone came in and told us what was going on and the professor turned on the TV. We had previously studied the towers as they were of important structural significance (as a case study) because of the system being an “exoskeleton”. Our professor was an M.I.T. grad, and although he was kind of an ass he was brilliant. He watched the TV for a moment, got really quiet and then started writing out this really long equation on the board that had to do with the temperature of fire with an accelerant and what’s called the “bending moment” of steel. He kept going with several other calculations that were beyond what he had taught us and then turned and told us that the tower was going to fall in x amount of time (I don’t remember exactly what he said) He was off by about 10 minutes, but I’ll never forget that. Huge lecture class and no one said a word.

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u/TrukkerJoe36 5d ago

Here's an article from Wired magazine in 2001 describing the audiotape released by the Pentagon of Bin Laden caught on tape saying that all they hoped for was that the plane would destroy the area where the plane hit and all floors above it.

So no.

https://www.wired.com/2001/12/bin-laden-caught-on-tape/

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u/thatvillainjay 4d ago

I was in school watching it on the black cart crt TV

I remember after the second plane hit we were watching the burning and a physics teacher there said very deadpan "it's going to collapse" and sure enough it did

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u/smackjack 4d ago

watching 9/11 in school was such a surreal experience. Having us watch what was happening live was kind of a fucked up thing to do in retrospect, but no one questioned it at the time.

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u/TFielding38 4d ago

I was in Elementary school on the west coast, so everyone saw it and heard about it on TV and Radio before school, because it was all our parents were doing. My school decided to just ban all discussion of it that day. Child rumor mill made us decide that our random suburb was the next target.

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u/tmahfan117 5d ago

I don’t know if they KNEW it would collapse, but I think they expected that to be a possibility.

Because the big difference between 9/11 and previous high rise fires is the collision itself. The steel columns of the twin towers were covered in fireproofing and rated to withstand several hours of fire. But during the crash, that fire proofing was physically smashed away exposing the steel directly.

And, a “normal” structure fire wouldn’t violently sever and destroy the water lines feeding the sprinkler systems, meaning you could expect some of the buildings built in fire protection system to keep working.

But really, the fire proofing is the bigger thing. Cuz in a high rise fire there really isn’t a lot of flammable material. If your office floor has enough wooden desks and carpet and paper to keep a fire going for an hour straight, well, then the columns that are coating in fire protection rated for 3 hours should do just fine.

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u/Christmas2025 5d ago

high rise fires

This is another reason we know the hijackers had no idea it would collapse; the reason they hit so high is likely based on the fact that in previous “high rise fires” it was understood that the higher the fire, the harder it would be for the fire dept. to extinguish it. They — as well as most everyone else — expected the fire department to eventually put the fire out.

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u/El0vution 4d ago

Ah! Finally an answer to my question as to why they hit so high up! And makes sense too.

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u/NysemePtem 5d ago

The fuel from the planes also played a role, their tanks were full.

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u/NuclearFamilyReactor 5d ago

I worked at a mesothelioma law firm for a few years in the early 2000s, and we defended corporations against individuals who had been exposed to asbestos at their jobs. (Yes it was a terrible first law firm job, thank you.) And in my training for the job I had to learn all about asbestos. The guy training me said that the reason the twin towers came down so easily is because asbestos had been made illegal at the time the towers were built, but that they hadn’t found a good fireproof insulation to replace it yet. 

I don’t know if this is true, or if he was just an asbestos shill, as I have yet to ever find a single article to back up what he said. And nobody else ever mentioned it. But there it is. 

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u/CitebDey 5d ago

They used a lot of asbestos in the North Tower for fireproofing. It was outlawed in the 1970s after they finished construction on the North Tower. When technicians took samples of the dust after the collapse they found asbestos fibers in the dust so first responders were exposed.

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u/NuclearFamilyReactor 5d ago

That sucks. Yeah I just found an article saying that above the 40th floor there was no asbestos. Maybe that’s what my trainer was referring to. In any case, it may have aided in the faster collapse. 

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u/tmahfan117 5d ago

He was wrong is why, the twin towers were built in the early 70s and contained plenty of asbestos 

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u/FoolAndHerUsername 5d ago

Despite the apparent recording of Bin Laden's expectation, there's previous statement from him after a car bomb damaged the foundation where he said "if I had more money, the tower would fall" (paraphrased). So, I'm surprised he said he didn't expect it.

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u/GodzillaDrinks 5d ago edited 4d ago

Pretty much no one expected the Towers to collapse. Fairly early in the disaster Police were urging people to return to their offices and not to evactuate. They were doing that because the most similar disaster up to that point was the 1 Meridian Fire in PA. Which was a fully involved fire in an office building that killed a team of firefighters before burning itself out more or less un-eventfully. If I recall correctly, in One Meridian, they just rebuilt the floors damaged by the fire (I didn't, thanks /u/HHoaks). The sprinklers and fire-proofing adequately contained the worst of the fire.

A lot of things contributed to the WTC collapse. Including improperly installed fire-supression materials, shoddy 1960-70s construction in general, and the fact that being hit by passenger jets isn't a failure condition that you can plan around. Several things that would have made a difference just didn't work. The Firefighters and EMS on scene had radios, but the radios crapped out approaching the towers and were completely useless inside preventing pivotal communications. Additionally, the spirnkler systems just didnt have the water pressure to handle all 3 buildings, and what water that did make it probably stopped after the first building fell on the pipes.

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u/csonnich 5d ago

IIRC, they started building skyscrapers with airplane crashes in mind after a B-25 bomber hit the Empire State Building in the 40s, but nobody expected a passenger jet to ever get that out of control. 

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u/GodzillaDrinks 4d ago edited 4d ago

Oh yeah, I had completely forgotten about that!

Still, there is quite a difference from a B-25 (68' wingspan) and a 767-222 (156'). Plus, I'm pretty sure the B-25 had more leg room.

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u/Mcgoobz3 5d ago

Lots of corners were cut in the construction of these buildings.

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u/GodzillaDrinks 5d ago edited 4d ago

Yup! Plus It was New York in like the 60s and 70s. So your concrete was reinforced with a bit of rebar here and there, but mostly with finks who tried to turn State's Evidence*.

Though the particular fire-proofing used was new at the time, and its pre-youtube. So I'm guessing that was done wrong by accident.

*Pretty sure I stole this joke from November on the WTYP Pod.

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u/Sheila_Monarch 4d ago

I don’t think I’ve heard the word “fink” since 1978. I had to think a minute on what it meant.

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u/ronmsmithjr 4d ago

My god, so many mentally disturbed people believing the US government planted explosives. Steel weakened enough that it couldn't support the floors above it. That's what happened morons. Please go back to talking about the flat earth or whatever other moronic things your underdeveloped brains cans think up.

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u/j_grouchy 5d ago

You know, it wasn't just fire. It also had something to do with the fact that 180 tons hit the support structure at a speed of over 200 miles per hour.

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u/I_read_all_wikipedia 5d ago

200? Try nearly 500.

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u/Accomplished_Baby_28 4d ago

I wouldn't try that

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u/BeefyMcPissflaps 5d ago

Oh they were well over 200mph. Those airplanes cruise at 400+kts over the ground.

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u/j_grouchy 5d ago

I'm sure. I know they go over 600 at full cruising, but I really have no idea how fast they were going when they hit. I only know they have to be at minimum of almost 200 to even stay in the air

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u/BeefyMcPissflaps 5d ago

Pilot here. They were definitely doing well over 250kts. I believe I read the Pentagon airplane was pushing 500kts at impact. Your thoughts are accurate though.

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u/Eric848448 5d ago

Pretty shocking how little visible damage it did to the Pentagon. I know it’s a massive building but still.

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u/damnedifyoudo_throw 5d ago

Recently renovated building designed to withstand a missile explosion. The plane basically disintegrated

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u/WellWellWellthennow 5d ago

But the buildings stood for an almost another hour. It was the fire that weakened the steel that caused the collapse.

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u/WellWellWellthennow 5d ago

The estimated the planes hit at around 400 and 500 mph.

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u/burn_as_souls 5d ago

This was talked about back when it was new.

Bin Laden himself said it was, in their eyes, a happy accident as far as no one knew the buildings would actually collapse.

The plan was merely crashing into them.

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u/BeKind999 5d ago

No I think they just wanted to wreak havoc and scare the shit out of everyone.

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u/P3for2 5d ago

No, that was unexpected. And to all the conspiracy theorists out there, no, it was not a bombing that collapsed the buildings. When you've got fires creating temperatures of over 1,000F, that's going to compromise the structural integrity of the building. There was also an apartment building in Florida that collapsed in that pancake manner a few years ago, the Surfside Condos. To say the WTC was a conspiracy, you'd have to say the Surfside Condos was a conspiracy too. They just, simply put, could not hold themselves up with all that weight stacked on top of it when it was falling.

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u/Screwthehelicopters 5d ago

I remember, just before 9/11, I spoke to a construction guy about some local supermarket construction I had seen. These supermarkets had a standard construction with a large curved roof supported by thick, composite wooden beams, like 3 feet deep, you could see from inside. When I asked him why not steel, he said (counter-intuitively) it was because of fire risk. In case of fire in the hall, the heat would lead to steel beams quickly losing their rigidity and collapsing. There was not even much weight on the roof, but the steel construction would collapse under its own weight long before the temperature reached the melting point of the metal.

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u/Jolteon0 5d ago

Jet fuel can't melt steel beams, but it can make them about as strong as silly putty.

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u/chopper5150 4d ago

Firefighter here and just wanted to mention that if anyone wants a really good breakdown of the failure of the Towers that led to collapse Fire Engineering magazine has a 4 part series of articles that explains everything in layman's terms. https://www.fireengineering.com/fire-prevention-protection/building-construction/the-world-trade-center-construction-and-collapse-part-1/

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u/NeverEnoughSunlight 5d ago

Possibly.

It was public knowledge each tower could sustain the impact of a Boeing 727, a narrowbody 150-seater:

  • The 757 is like a super stretch narrowbody with one less engine but two bigger Rolls-Royce ones.
  • The 767 is a widebody with not three but two even bigger engines.

Both carry way more fuel than a 727.

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u/CaptainObviousBear 4d ago edited 4d ago

Bin Laden thought the towers would collapse from the point of impact and above it, but not below it. This is from a transcript that you can read here:

UBL: (...Inaudible...) we calculated in advance the number of casualties from the enemy, who would be killed based on the position of the tower. We calculated that the floors that would be hit would be three or four floors. I was the most optimistic of them all. (...Inaudible...) due to my experience in this field, I was thinking that the fire from the gas in the plane would melt the iron structure of the building and collapse the area where the plane hit and all the floors above it only. This is all that we had hoped for.

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u/WillingnessDry1699 4d ago

I think 9/11 was way more "successful" than what Bin Laden was expecting.

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u/SidFinch99 4d ago

They specifically chose to hijack flights with long flights because those would have the most fuel and they believed would burn hot enough to weaken or melt the beams. They didn't expect all the floors below to collapse iirc.

Because the blast impact broke off a type foam like fire proofing around the beams. Incense fire and heat spread to beams further down, weakening the structures more.

The death total was exacerbated by the inability to evacuate quickly, including there being protocols for many to stay in place because there had been a belief the towers couldn't fall.

Also. It being basically impossible for fire fighters to get up to the floors necessary to attach hoses to spouts and try to stop the burning from spreading.

One of the more heart breaking things caught on camera is the images of firefighters hugging one another before going in knowing they were pretty certain to not come out, but feeling the need to try anyway.

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u/KindAwareness3073 5d ago

Osama bin Laden owned a construction company and he had an engineering degree. When the 1993 attempt to blow up the towers failed I suspect they put a lot of effort into the plan.

I studied the engineering of the towers in school (before 9/11) and they were taught as a remarkable example of minimalist engineering. Did they "know" they'd collapse? No. Did they have reason to hope? Yes.

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