BYU Professor: Explosives Used To Bring Down WTC

[dinAlt]

You're trying to make the case that asymmetric fire damage logically results in an asymmetric collapse, but others have shown this is probably not true, and that the WTC buildings had asymmetric collapses anyways. Your 'logical' relation between A and B is meaningless if the entire premise is not factual. The premise "If A, then not B" is factually wrong, even if logically consistent.

This is precisely the point I was making. The logic is sound, but the premises are in dispute. The logic is solid, but if either premise is untrue, unknown, or unknowable, the conclusion is either incorrect or meaningless.

In this case, the premise is unknown, but it is not unknowable, which makes the conclusion meaningless until the premise has been falsified or confirmed. A number of people have given their opinion, but so far I have yet to see anyone who should be regarded as an expert, a structural engineer, say anything definitive on the matter. No weight should be given to ad hok theories by non experts arguing for or against this premise, as it involves a very complex system, which may be non-intuitive.

The argument that it 'could' have happened, because unlikely things do happen, is not going to convince the conspiracy crowd, who just like the other side of this debate, prefer to fill the unknowns with what they would like to believe. If this issue could be resolved with a high degree of certainty, then we can finally drop this matter into the dust bin and move on.

[akirabakabaka]

Thanks for the educational replies, JayUtah. You've at least helped me understand the weight of the simulations upon the investigation. I'm still convinced a proper investigation at the time of the attack would have answered every problem encountered on these threads, but NIST et al. really appear to have done the best they could given the circumstances. Just about all of my concerns have been satisfied; the rest are hampered by the destruction of evidence but I think some clues still remain...

I'm still interested in William Rodriguez and what actually happened in the basement levels. I just came across this transcript from the afternoon of 9/11. People drowning in elevators? Does anyone know if a serious investigation was ever conducted on destruction in the basement levels? Sources are much appreciated. I'll also make a quick comment about fuel from the jets falling down 80+ stories in an elevator shaft. Has this ever been quantified as being even remotely possible?

[Peter B]

Akirabakabaka said:

I'll also make a quick comment about fuel from the jets falling down 80+ stories in an elevator shaft. Has this ever been quantified as being even remotely possible?

I'm looking forward to your comment, as I can't see how it's a problem. We know it would take little more than 6 seconds to fall that distance if it wasn't burning, and I doubt it would all burn in 6 seconds.

[JayUtah]

I'm still convinced a proper investigation at the time of the attack would have answered every problem encountered on these threads...

But while some people complain that the actual investigation was "incomplete", others would complain that a more extensive investigation would be wasteful because it addressed issues that were not seriously in dispute. You can't please everyone.

The "problems" you and others have identified aren't all really problems. You can't call it a problem in the objective sense if all you can say about it is that it doesn't make sense to you. What I might call a problem in, say, dentistry might not be considered a problem by a qualified dentist. The "problem" in that case would be my lack of expertise in the field.

Now perhaps you could say that NIST should have written its report so as to be comprehended by the layman, but then it would be volumes. As with most real-world investigations and findings, the reader has to rise to a certain level of personal competence in order to understand it fully.

Ironically this was one of the debates among the Founding Fathers against democracy. (Keep in mind that they were writing at a time when there was a wide gulf between the laity and the educated.) But their argument was that government and power should not be given over to a naive citizenry; government was so important that it should be undertaken only by the highly educated and well-trained.

The NIST summary report can be understood to a certain degree by the layman; but to truly understand how and why it constitutes a valid approach to the investigation requires a fairly extensive knowledge of how those methods came about. It has taken me more than a decade to learn enough about these techniques to be comfortable discussing them. Anyone can learn about them, but first they have to realize that they must learn about them. Too many people are content to apply no more understanding than they already possess. That's not a good approach to democracy.

...but NIST et al. really appear to have done the best they could given the circumstances.

I think they did. Could they have done some things differently? Probably. Was there a political influence? Probably. Will we -- the world at large -- continue to study the disaster? Without question. As I'm fond of pointing out, we're still studying the Titanic disaster, and that was almost a hundred years ago. As we get new tools, we apply them to past problems. Not because we need necessarily to revisit them, but because that activity increases our depth of understanding.

...the rest are hampered by the destruction of evidence but I think some clues still remain...

I think some of the rhetoric regarding the disposition of the debris has been overstated. Normally in a collapse scenario we would do a forensic removal of the debris. We'd photograph every piece and map its final position like archaeologists. But frankly we've never had an incident that created so much debris. I don't think we'd know what to do with millions of pounds of steel, only some of which really provided answers.

The need to rescue survivors and the need to restore basic operability to Lower Manhattan outweighs the need to preserve the "crime scene". Forensic engineering has always accepted that exigent needs at the time may disrupt the evidence.

I'm still interested in William Rodriguez and what actually happened in the basement levels.

As am I. I'm abstractly curious, though. I don't think it had anything to do with why the buildings fell down, but that doesn't mean it's not worth learning about. I just don't feel personally that W. Rodriguez is a good source from which to learn them.

But whether a basement "explosion" is a pressure wave or a terrorist bomb, it still had a destructive effect. I don't think there's much evidence it was a terrorist bomb, but we need to anticipate those kinds of effects the next time an airplane hits a building. It may be incumbent on engineers to figure out a way to vent such pressure waves non-destructively and make a building that safeguards life better.

I'll also make a quick comment about fuel from the jets falling down 80+ stories in an elevator shaft. Has this ever been quantified as being even remotely possible?

Well, water does. So I don't think it's impossible for kerosene to do that. If you've got an 80-foot shaft, then something released at the top will fall all 80 feet, unless it hits an obstacle (e.g., the elevator). Fuel will flow around the elevator car. The worst thing is if the fuel vaporizes or aerosolizes as it falls; you want it to fall all the way and land in a puddle where it can be drained off or otherwise safed as a mass of liquid. The worst-case scenario is an 80-foot shaft full of fuel vapor and air. That's a big bomb waiting to go off.

[JMV]

I noticed that Van Romero's statements were still used to counter debunkers' argument of enormous amounts of explosives, even though JayUtah had already pointed out in his post that Van Romero is talking about the amount of explosives needed to only collapse the towers (if they were to have been brought down by explosives that is), whereas debunkers' argument concerns Hoffman's "energy deficit" -claims regarding the pulverization of the building materials.

[Alan G. Archer]

Just a bit of nitpicking, Jay, but didn't you mean an 80-story shaft, not an 80-foot shaft?

Edit: Grammar

[dinAlt]

It has been; but people reject the results largely for political or ideological reasons. Oh sure, they try to offer evidentiary reasons, but they boil down simply to an unsupported unwillingness to address the results. "How can these models work?", etc. That's just FUD. They're trying to undermine credibility at all costs, regardless of whether the objection actually makes sense. It goes back to people thinking that their intuitive and simplistic understanding of something is equivalent to that applied by experts.

Once again, thank you for your excellent reply to my question. You have provided enough solid information to have reasonable confidence in the official hypothesis. While it is true, there are many in the conspiracy crowd, who will not accept any evidence contradictory to their beliefs, there are also many, who are willing to objectively evaluate the evidence. This second group tends to be far less vocal, as such they are underrepresented. Thank you for taking the time to address this matter.

When presented with the unknown, homo sapiens have a tendency to fill the unknown with their worst fears. This is what drives conspiratorial thinking. If knowledgeable people fail to address the matter in an open public forum, they will assume their fears have been confirmed. A tremendous amount of damage is being done to this country by the excessive secrecy of the current administration and their unwillingness to directly address the issues raised by the 9/11 conspiracy crowd in a serious manner. It is not healthy to have a quarter of the country believing their government was complicit in the murder of its own citizens.

There is a second crowd, who I have as much contempt for as the die hard conspiracists. This second group of people fills the unknown with what they would like to believe and will ignore or dismiss all evidence to the contrary, no matter how compelling, just as their wide eyed conspiratorial rivals. They believe their own government to be incapable of any form of malfeasance towards its own citizenry, despite ample historical precedent. This group of people is at least as dangerous to the national well being as the die hard conspiracist crowd. They feed conspiracism by systematically ridiculing all claims of governmental malfeasance. By doing so, they bring an end to rational discourse and drive the conspiracists underground, where they continue to proliferate, out of site and unchallenged. Their belief is also dangerous because their unwillingness to consider the possibility of governmental malfeasance provides the perfect environment for it to flourish.

[akirabakabaka]

Akirabakabaka said:

I'm looking forward to your comment, as I can't see how it's a problem. We know it would take little more than 6 seconds to fall that distance if it wasn't burning, and I doubt it would all burn in 6 seconds.

Minus the fuel expelled from the building, minus the fuel burned on impact, minus the fuel that doesn't drain down the shafts... this is the quantization I'm wondering about.

The two sources of destruction in the basement levels I've seen proposed are 1) fuel falling down the elevator shafts, and 2) someone on this thread suggested an electrical component.

From the Rodriguez transcript: "RODRIGUEZ: I was in the basement, which is the support floor for the maintenance company, and we hear like a big rumble. Not like an impact, like a rumble, like moving furniture in a massive way. And all of sudden we hear another rumble, and a guy comes running, running into our office, and all of skin was off his body. All of the skin."

I've seen 3 different versions of this guy's story. In one transcript of his testimony to the 9-11 commission (which was 'conspiratorially' not included in the final report) he says he heard the explosions at the time of impact. The day of the attack all he heard was 'rumbling'. Now he claims he heard explosions BEFORE the impact?

This transcript seems the most reliable of his reports. He heard the plane impacting (first rumble) and then soon after the basements exploding (second rumble). He's apparently turned 'rumble' into 'explosion' and reversed the order of events.

This sequence supports plane impact + fuel/energy down the shafts causing secondary explosions in the lower levels.

[twinstead]

...This group of people is at least as dangerous to the national well being as the die hard conspiracist crowd. They feed conspiracism by systematically ridiculing all claims of governmental malfeasance. By doing so, they bring an end to rational discourse and drive the conspiracists underground, where they continue to proliferate, out of site and unchallenged. Their belief is also dangerous because their unwillingness to consider the possibility of governmental malfeasance provides the perfect environment for it to flourish.

In many ways 'Harry see-a-conspiracy-under-every-bed' and 'Bubba the jingoist' are two sides of the same coin. Not only does Bubba feed Harry "by systematically ridiculing all claims of governmental malfeasance", but Harry in turn feeds Bubba by refusing to believe anything but malfeasance from the government.

They are equally dangerous and are impervious to rational debate; I like to avoid both.

[Peter B]

Akirabakabaka said:

The two sources of destruction in the basement levels I've seen proposed are 1) fuel falling down the elevator shafts, and 2) someone on this thread suggested an electrical component.

Actually, JayUtah has also suggested a pressure wave - I assume this means air compressed and blown outwards by the impact explosion. Following paths of least resistance would allow it to travel down lift shafts, and into the basement. Though I'll let Jay explain that in more detail.

[Cl1mh4224rd]

A tremendous amount of damage is being done to this country by the excessive secrecy of the current administration and their unwillingness to directly address the issues raised by the 9/11 conspiracy crowd in a serious manner. It is not healthy to have a quarter of the country believing their government was complicit in the murder of its own citizens.

I think you grossly overestimate the number of people who believe this. Twenty-five percent is hardly insignificant (~74 million people). If the number was that high, there would be significant protests in front of the White House. I am personally unaware of any such event in the context of some 9/11 conspiracy.

[Van Rijn]

A tremendous amount of damage is being done to this country by the excessive secrecy of the current administration and their unwillingness to directly address the issues raised by the 9/11 conspiracy crowd in a serious manner. It is not healthy to have a quarter of the country believing their government was complicit in the murder of its own citizens.

I'd like to see where you got those numbers. I haven't personally met anyone offline that said they believed in a 9/11 conspiracy, though I do know quite a few people that can't stand Bush.

From what I've seen online, my impression is that the majority of 9/11 conspiracy believers are so anti-Bush and anti US Government that no rational argument will change their minds. If anything, my guess is that more emphasis on 9/11 would probably just make them think that there "must be something to it" and most CBers would just call it a "disinformation campaign."

There is a second crowd, who I have as much contempt for as the die hard conspiracists. This second group of people fills the unknown with what they would like to believe and will ignore or dismiss all evidence to the contrary, no matter how compelling, just as their wide eyed conspiratorial rivals. They believe their own government to be incapable of any form of malfeasance towards its own citizenry, despite ample historical precedent. This group of people is at least as dangerous to the national well being as the die hard conspiracist crowd.

Of course, but there has to be evidence. Good evidence. Sadly, there are always rumors of conspiracies, and they often follow the extremes of the political parties. People who believed that Clinton had hit men would never consider anything negative about Bush, and vice versa.

[Tolls]

Well, water does. So I don't think it's impossible for kerosene to do that. If you've got an 80-foot shaft, then something released at the top will fall all 80 feet, unless it hits an obstacle (e.g., the elevator). Fuel will flow around the elevator car. The worst thing is if the fuel vaporizes or aerosolizes as it falls; you want it to fall all the way and land in a puddle where it can be drained off or otherwise safed as a mass of liquid. The worst-case scenario is an 80-foot shaft full of fuel vapor and air. That's a big bomb waiting to go off.

I dug around on FAEs and pulled up this if anyone's interested.
http://www.fas.org/man/dod-101/sys/dumb/fae.htm

There's a formula down near the bottom for the distance at which you'll get a 1psi overpressure for a particular amount of fuel. I don't have any figures for plugging into the equations, but maybe someone else does to see what would happen if a lift shaft of aviation fuel vapour detonated. I suspect, as Jay says, it would be a rather big bang, explaining any boom in the basement.

It ought to be noted that:
"High flame front speeds and resulting high blast over pressures are seen in accidental vapor cloud explosions where there is a significant amount of confinement and congestion that limits flame front expansion and increases flame turbulence."

Which, if I read that correctly, would mean a bigger blast effect over a larger distance than the calculation would give.

[Ken G]

I am glad that dinAlt is willing to look at evidence and allow opinions to change. That is actually somewhat unusual in a debate of this nature! But I would point out a caveat to this:

Their belief is also dangerous because their unwillingness to consider the possibility of governmental malfeasance provides the perfect environment for it to flourish.

I agree that governments are quite capable of malfeasance, to any population including their own. History makes this amply clear. So we must not assume that we are always the "good guys", for that assumption will make us blind to evidence to the contrary. But conspiracy theorists actually hinder this educational process, because they afford the government with so much power and so much evil intent that the CTs cannot possibly provide any constructive solutions. If they wish to make the world a better place by serving as government watchdogs, they are doing as poor of a job as an actual watchdog that lets the robbers get away, because it is so busy growling at every shadow in the courtyard it can't tell the difference when a real threat appears.

[kookbreaker]

I agree that governments are quite capable of malfeasance, to any population including their own. History makes this amply clear. So we must not assume that we are always the "good guys", for that assumption will make us blind to evidence to the contrary. But conspiracy theorists actually hinder this educational process, because they afford the government with so much power and so much evil intent that the CTs cannot possibly provide any constructive solutions. If they wish to make the world a better place by serving as government watchdogs, they are doing as poor of a job as an actual watchdog that lets the robbers get away, because it is so busy growling at every shadow in the courtyard it can't tell the difference when a real threat appears.

Very well put. Thanks!

[JayUtah]

Just a bit of nitpicking, Jay, but didn't you mean an 80-story shaft, not an 80-foot shaft?

Yeah, probably. I thought I was copying what was in the original post. And I got thinking of that this morning: 80 feet isn't really very far. I'll have to look at the elevator schematics again to see what the alleged fuel paths are. And I wasn't considering that the fuel was burning on the way down. Kerosene doesn't burn as a liquid; it has to be vaporized. But dumping it into free-fall isn't a bad way to vaporize it. So I'm not sure you can start with some given liquid mass of fuel and have it fall 80 stories with guaranteed ignition and have it reach the bottom.

But if the fuel ignites in the shaft, you will have a gun-barrel effect that has already been mentioned. You would turn the entire elevator shaft into a gigantic spud gun, even with a small amount of fuel. So while the fuel itself might not fall the entire way, the flame front would likely traverse the entire distance.

[JayUtah]

DinAlt, I think you've made a very important observation, and that's that implicit belief causes problems regardless of what is believed. People who implicitly trust authority and people who implicitly distrust authority are as polarized as they can be about what they believe, but they are identical when it comes to why they believe it.

And, ironicly, both play into the hands of an unscrupulous authority. People who never question authority obviously pose no threat. But people who always question authority can be written off as kooks, even if once or twice they do happen to have a good point. Most conspiracy theories that are discussed here have a very shaky factual basis. That makes them easy to dismiss with good arguments, and it creates the impression that people who criticize authority really don't know what they're talking about. It dilutes credibility for the legitimate criticism.

This also applies outside of government. We once invited one of our "problem" customers to make a frank assessment of our ability to deliver working solutions. They identified a number of very legitimate areas in which we might improve, but also made a few fairly naive suggestions. (The customer is a government agency, and therefore not the best people to turn to for advice on how to run a business.) Despite the many spot-on observations, some of the management used the gaffes as an excuse to dismiss the entire presentation as ill-founded. You simply don't want to give people an excuse not to listen to you -- however irrational it would be to ignore you.

[akirabakabaka]

But if the fuel ignites in the shaft, you will have a gun-barrel effect that has already been mentioned. You would turn the entire elevator shaft into a gigantic spud gun, even with a small amount of fuel. So while the fuel itself might not fall the entire way, the flame front would likely traverse the entire distance.

From all of the witness testimonies this really sounds like the most likely scenario. The people injured in the blasts were all near the elevator shafts. The open space of the lobby allowed just the windows to be blown out as this passed, but it appears the main force discharged in the confined basement areas.

There were also reports of various other things in the elevator shafts.. some cars fell, some took other damage, and I've only heard of any of this happening in WTC1. WTC2 took a glancing blow from the plane so little fuel/energy must have transferred to the shafts, while the WTC1 impact was dead-on. Any of this sound reasonable?

[dinAlt]

I'd like to see where you got those numbers. I haven't personally met anyone offline that said they believed in a 9/11 conspiracy, though I do know quite a few people that can't stand Bush.

The number was arbitrary, for the sake of the larger point I was making: we do not want to reach that point. I am unaware of a reliable national poll on the matter, but we do have numbers for New York.

http://www.zogby.com/news/ReadNews.dbm?ID=855

As for not having met anyone who holds this view, I would like to point out the topic is taboo in polite company. If you need to be convinced of this, try the following experiment. Go discuss the matter with your friends, relatives, and coworkers, while playing the devils advocate in your most sincere voice. Use only the strongest arguments for controlled demolition; avoid the more off-the-wall material. It does not matter if you can effectively counter your own arguments.

I must warn you: I have already tried this and it is an ugly experience. It may cost you friendships, damage family ties, and/or damage your reputation at work. I no longer engage anyone in conversation along these lines with anyone who I care to retain a working relationship with. Of the people I have talked to, about 1/4 of them were believers, but they never would have said anything if I had not broached the subject first. The remainder were unwilling to participate in a rational discussion and were generally hostile and angry, as such heretical ideas are apparently 'Unamerican.'

[JayUtah]

I wouldn't necessarily call the impact at WTC 2 a "glancing" blow, since the entirety of the airframe hit some structure. But I know what you're getting at, since a clear deflagration is visible to the side of the impact area; rather than going mostly through the opposite wall.

More important than the angle of approach is the orientation of the core. Recall that the WTC floor plans are square, but the core plan is rectangular. That means the distance from perimeter to the outer boundary of the core is long in one dimension and short in the other. The WTC 1 impact was on the "long" side, so even thought it was a more direct impact, there was more structure to plow through before reaching the core. The WTC 2 impact was on the "short" side, so more of the airframe was intact when the core was encountered. You could argue in the handwaving sense that the fuel tanks stood a better chance of reaching the WTC 2 core intact and then dumping their fuel down the core vertical shafts.

[akirabakabaka]

I really wonder if any of this happened in the WTC2 basements. Wasn't anybody down there?

[dinAlt]

I agree that governments are quite capable of malfeasance, to any population including their own. History makes this amply clear. So we must not assume that we are always the "good guys", for that assumption will make us blind to evidence to the contrary. But conspiracy theorists actually hinder this educational process, because they afford the government with so much power and so much evil intent that the CTs cannot possibly provide any constructive solutions. If they wish to make the world a better place by serving as government watchdogs, they are doing as poor of a job as an actual watchdog that lets the robbers get away, because it is so busy growling at every shadow in the courtyard it can't tell the difference when a real threat appears.

I agree. The core conspiracists do a great deal of harm to their own cause. I am reminded of the parable of “The Boy Who Cried Wolf.” They make the claim of conspiracy so often and with so little evidence that no one pays attention to them. This raises the danger that if the wolf ever does arrive, we may not notice until it is too late. There are far too many historical examples of republics, which have fallen into tyranny, because the populace could not believe it could happen to them. It could be argued that both sides of the “true believer” coin have contributed to this phenomenon.

Most conspiracy theories, with a little bit of investigation, can either be demonstrated to be false or at least unfalsifiable, yet there are still a small number of instances of what appear to be outlandish conspiracy theories, which turn out to be true (see the Wikipedia's entry on 'Conspiracy Theory' for examples). This should serve as a warning to those who dismiss all claims of conspiracy out-of-hand, without examining the evidence.

I understand it can be frustrating to deal with the overwhelming quantity of bogus claims put forth by the conspiracy crowd. If you do not have the time to examine the evidence of a particular claim, it is proper to tentatively assume such claims are false on purely statistical grounds. Without having investigated it yourself, you do yourself and others a great disservice by taking a strong position on such matters by deriding the proponents of conspiratorial claims. By making the subject of conspiracy taboo, all discussion of such matters is withdrawn from the domain of rational discourse and this only serves to harm both sides.

As for those who believe small scale corruption is possible, but large scale malfeasance by government is out of the question, I will close my argument with the following quote.

Hitler writes in Mein Kampf (James Murphy translation, page 134):

“All this was inspired by the principle - which is quite true in itself - that in the big lie there is always a certain force of credibility; because the broad masses of a nation are always more easily corrupted in the deeper strata of their emotional nature than consciously or voluntarily; and thus in the primitive simplicity of their minds they more readily fall victims to the big lie than the small lie, since they themselves often tell small lies in little matters but would be ashamed to resort to large-scale falsehoods. It would never come into their heads to fabricate colossal untruths, and they would not believe that others could have the impudence to distort the truth so infamously. Even though the facts which prove this to be so may be brought clearly to their minds, they will still doubt and waver and will continue to think that there may be some other explanation.”

[twinstead]

As for those who believe small scale corruption is possible, but large scale malfeasance by government is out of the question, I will close my argument with the following quote.

I would imagine that even Hitler would have balked at the incredible complexity and risk of a moon hoax or 911 hoax type of lie.

[dinAlt]

I would imagine that even Hitler would have balked at the incredible complexity and risk of a moon hoax or 911 hoax type of lie.

Edit -- The original post made use of sarcasm and this was inappropriate.

See: Reichstag Fire

[twinstead]

dinAlt do you really believe the Reichstag Fire is equivalent to 911, in terms of how complex it was?

[twinstead]

As an aside, I realize that the Reichtag fire is a case study in how a democracy can be destroyed by creating a law-and-order crisis and offering as a 'solution' the abdication of civil liberties and state's rights to a powerful but unaccountable central authority.

My point is sometimes a crisis can be made up and sometimes it is real. What are the criteria for deciding if it is real or not?

[Alan G. Archer]

I really wonder if any of this happened in the WTC2 basements. Wasn't anybody down there?

Officer David Lim and his Explosive Detection Dog, Sirius, were on level B-1.

[turbonium]

I read the article with David Lim. It's rather interesting...

He says he was on the 4th floor when it collapsed, after which he and 13 other people were still alive in the stairwell.

After about 5 hours, they "managed to find our way out by an opening on the 6th floor".



Indeed.

[Alan G. Archer]

I read the article with David Lim. It's rather interesting...

He says he was on the 4th floor when it collapsed, after which he and 13 other people were still alive in the stairwell.

After about 5 hours, they "managed to find our way out by an opening on the 6th floor".

http://tinypic.com/i4fm08.jpg

Indeed.

See Juliet Macur's story for The Dallas Morning News, "Days of digging, grieving: Only one New York fire company got out with every man alive."

From the stairwell, Billy Butler tried to call 911, using the phone of a Port Authority officer who was trapped with them. When he couldn't get through, he called his wife in Greenville, N.Y. After countless busy signals, he got a connection.

"Diane, we're trapped in the World Trade Center, but I'm OK," he said.

Diane Butler started whimpering. But her husband told her she had a job to do. She was to call the authorities for help.

"Tell them we're in tower one, in the B stairwell at about the fourth floor," he said. "Calm down. You have to do this."

[...]

For more than four hours, Billy Butler and his group of survivors waited for help that didn't come. Then a ray of sunlight hit his shoulder.

Somewhere in the wreckage above them was an opening. Leaving Josephine behind, the men scrambled toward it – and emerged into a world that, even with all they had been through, they could not have imagined.

Mountains, acres of smoldering rubble. Hulking steel silhouettes, surreal in the smoke. And above, nothing. Where a 110-story building had stood, a wasteland.

[Alan G. Archer]

Of course, David Lim was in North Tower (WTC1) when the South Tower was attacked.