not needed to prove complicity
once the fact that 9/11 was allowed to happen was established (which was documented within a few weeks of the events), everything beyond that is merely detail.
Much of the energy in the "9/11 truth movement" has long since passed over pointing out the seemingly mundane issue of official foreknowledge of the attacks and is now focused on claims the towers (and WTC 7) were deliberately blown up, plane crashes were faked, and even more obscure and extreme claims. But the political implications of "merely" allowing the attacks to happen is not much different than the controlled demolition claims. Arguing over the precise technical support given to 9/11 by the national security state is similar to debating the number of bullets fired at President Kennedy -- perhaps it may be interesting (or morbid) to a tiny minority, but irrelevant for understanding the Big Picture.
Even if it is true that uninterruptable autopilots were used to "hijack the hijackers" with remote control (to ensure the planes hit their targets, and not the Indian Point nuclear power station, which Flight 11 flew over, and also not Rumsfeld's office in the opposite side of the Pentagon that was hit), that would not change the situation -- the covert government wanted, needed, enabled the 9/11 attacks. Regardless of the precise manner that 9/11 was facilitated, the "security theater" (to use security consultant Bruce Schneier's term) at the airports is a distraction from accountability for allowing the attacks to proceed despite ample warnings from US allies, FBI agents and military intelligence.
I have a legal case that will convict Dick Cheney, Donald Rumsfeld, George W. Bush, General Myers, right now in court based upon evidence that is not scientific in nature, I don't need to go there, that is a red herring when we focus on the crime that has been committed against this country. We've already proven who did it, the how doesn't have to be fully fleshed out. ...
These discussions of what possibly induced that [collapse of the towers] is a major psychological operations campaign designed to keep the American people from looking at the evidence of guilt.
-- Michael Ruppert, February 14, 2005, interview on KZYX, "The Party’s Over"
The case of 9/11, now being tried in our metaphorical court of the corporate media and public perception, leaves no doubt as to who could produce more expert witness testimony or present them in the most impressive manner. ... It is something else to analyze the temperature at which steel is weakened and determining whether or not an unproven amount of burning jet fuel, in unspecified concentrations and unknown locations could have weakened steel supports in the World Trade Center to the point where an unspecified amount of weight might cause them to buckle.
-- Michael Ruppert, Crossing the Rubicon: the Decline of the American Empire at the End of the Age of Oil, pp. 13-14
The position of oilempire.us is that the towers were intentionally demolished by the Bush administration, but the method of destruction was allowing (and possibly steering) Flight 11 and Flight 175 to crash into the buildings. Claims for explosives, thermite, and even exotic unconventional weapons are not supported by peer reviewed, independently verifiable investigations and are an enormous distraction from solid evidence. The core of the case for complicity has nothing to do with the collapses.
It is reasonable to assume the impacts of the planes plus the blast furnace type fires were sufficient to ensure the collapse of the towers. It is fortunate they remained standing long enough for those below the impact zones to escape.
The official complicity to let it happen and provide technical assistance resulted in demolition, but not in the scenario that much of the "truth movement" postulates.
The evidence for suppression of numerous warnings, interference with investigations of the flight schools before 9/11 and the multiple exercises on 9/11 was more than enough for an impeachment and conviction for aiding and abetting. Further details are like arguing whether the Reichstag in Germany was burned with gasoline or kerosene -- while the camps for dissidents are being completed for use. As with the Kennedy assassinations, the real issues are WHY 9/11 was allowed to happen, not the fine details of how it was technically accomplished. We are as unlikely to know the precise mechanisms behind 9/11 as the identity of the shooters of John F. Kennedy and Robert F. Kennedy, but why these crimes were committed is much less obscure, and a more fruitful path for serious investigation that could lead to positive social changes.
If there is any truth to the demolition theories, it is unlikely to be found in the loudest promotions of these claims (Loose Change, Scholars for 9/11 Truth), which is why the media strategy is to focus on these alleged investigators and not those who highlight much better evidence that is not easily attacked.
One parallel between investigating 9/11 and the JFK assassination is both scandals suffer from the problem of independent investigators focusing solely on minutiae instead of the big picture. Why these crimes were carried out - and covered up by the media and political establishments - is more important than the technical details of how the violence was perpetrated.
The third skyscraper that collapsed - Building 7 - was hit by substantial debris from the collapsing towers, had more significant fires than reported by most 9/11 "truth" websites and videos, and the firefighters had concluded hours before its collapse that it was going to fall down, too.
As Carl Sagan famously said, extraordinary claims require extraordinary evidence. So far, there are not any verifiable, unshakeable proofs for demolition (even the best claims are inferential). Meanwhile, there is well documented evidence that shows abundant warnings from close US allies that were very specific to time, plane, means.
Some of the gaps not explained by any demolition theories:
- no analyses of the damage to the structures from the impact of the planes, which caused considerable damage. (Some who were in the towers thought the building was going to fall over when it happened.) The claim that fire alone caused the collapses is not the official story, even if many claim that it is.
- there was a noticeable bulge in the buildings just before collapse seems to refute the demolition theories -- although photos on websites are not of sufficient resolution to prove or disprove this aspect.
- how could potential explosives survive the impacts and infernos? How could they have been detonated at the same locations as the impact zones while surviving the fires (in the North Tower, for more than an hour and a half). While black boxes used in aircraft data recorders can survive the shock and heat of plane crashes (and they were found from all four 9/11 planes), their integrity is merely to ensure data recorded before the crash remains retrievable, they do not continue to function after extreme force and heat.
In the winter of 2005, the PBS network aired a show called “Building to Extremes” about the new rush to put up even more absurdly tall super-skyscrapers (Taiwan, Malaysia, Shanghai, etc).
The show had a segment about the WTC collapses that discussed a 2002 report from Weldlinger Associates that dispensed with the “pancake theory” Instead, they hypothesize that the collapse resulted from the heating of the steel to modest temperatures (steel, according to them, loses half of its load capacity at about 500 degrees centigrade, which is well within the range of temperatures in that inferno), and the loss of critical columns (from the impact of the planes). The engineer in the film claimed that the buildings would have survived the loss of the columns - via the roof truss structure that transfer load from the damaged / destroyed columns to intact columns - if it wasn’t for the fire that heated the steel to the point that it lost some of its structural integrity.
Some of the bogus folks on the web claim that without MELTING of the steel there was no chance for the official stories of collapse to be true, but they don’t talk about the reduction of integrity from the heating without melting. In addition, the engineer stated that the South Tower was more unbalanced from the lower hole than the North Tower, which is why it fell first (that is a reasonable claim). Finally, they discussed a smoke analysis that they did from the existing video and still footage that estimated temperatures and spread of the fires to justify their conclusions.
The demolition theory does not explain how the demolition charges would have stayed intact during the inferno.
Another problem with the demolition theory is that substantial proportions of the structure were destroyed by a high impact collision (and exactly what happened to the core columns is unknown and unknowable without access to the rubble). The "temperature of burning jet fuel was not enough to bring down the towers" is a fake claim, since the chimney effect (blowing air) plus the burning plastics, paper, etc would have increased the temperature considerably over the mere temperature of burning jet fuel.
The much stronger Pentagon building had a collapse about a half hour after the plane crash, so the collapse of the towers in roughly the same amount of time is reasonable. (The hoaxers don't claim that the collapse of the outside ring of the Pentagon was demolition -- instead, they claim there wasn't a plane crash even though there was).
One anomaly that no one can explain is why the rubble burned for months despite firefighting and rain, but that is not evidence for demolition. Controlled demolition does not result in months long fires. The claims for thermite do not explain this either. Bizarre claims for "nuclear weapons took down the WTC" are also easily dismissed (there are many aspects of the collapse that have no relationship to nuclear detonations).
November 10, 1999: North WTC Tower Suffers Last ‘Significant’ Fire Prior to 9/11; Bigger Fire Occurred in 1975
The North Tower of the WTC suffers a fire on its 104th floor. This is the 15th and last of what the National Institute of Standards and Technology later describes as “significant fires,” which occurred in the Twin Towers from 1975 onwards, and prior to 9/11. These fires each activate up to three sprinklers but are confined to just one floor. [KULIGOWSKI, EVANS, AND PEACOCK, 9/2005, PP. 7-11] Additionally, on February 14, 1975 a major fire occurred, the result of arson, which began on the 11th floor of the North Tower during the middle of the night. Spreading through floor openings in the utility closets, it caused damage from the 10th to 19th floors, though this was generally confined to the utility closets. However, on the 11th floor about 9,000 square feet was damaged. This was about 21 percent of the floor’s total area (43,200 square feet) and took weeks to repair. Some parts of the steel trusses (floor supports) buckled due to the heat. 132 firefighters were called to the tower in response, and because the fire was so hot, many got their necks and ears burned. Fire Department Captain Harold Kull described the three-hour effort to extinguish it as “like fighting a blowtorch.” [WTC ENVIRONMENTAL ASSESSMENT WORKING GROUP, 9/2002, PP. 10 ; NEW YORK TIMES, 5/8/2003; GLANZ AND LIPTON, 2004, PP. 213, 214, 324; KULIGOWSKI, EVANS, AND PEACOCK, 9/2005, PP. 1] An article in Fire Engineering magazine will later summarize, “[A]lmost all large buildings will be the location for a major fire in their useful life. No major high-rise building has ever collapsed from fire. The WTC was the location for such a fire in 1975; however, the building survived with minor damage and was repaired and returned to service.” [FIRE ENGINEERING, 10/2002] Building 7 of the WTC, which completely collapses late in the afternoon on 9/11, has also suffered a ‘significant’ fire in 1988, occurring on its third floor, with multiple sprinklers being activated. [KULIGOWSKI, EVANS, AND PEACOCK, 9/2005, PP. 12]
Entity Tags: World Trade Center
Timeline Tags: Complete 911 Timeline, 9/11 Timeline
The more people obsess about whether or not controlled demolition was involved in the WTC collapse, the more they play into the hands of BushCo by being distracted from inquiring about far more significant issues, such as the relationship among the ISI, the House of Saud, the "black bag" CIA operatives, and the neo-cons infesting the Bush administration. There has been plenty of research and documentation about this compiled by the Cooperative Research website of Paul Thompson and analyzed in the excellent book The War on Truth by Ahmed. Those leads need to be further followed up IMHO.
My education and career has been in architecture and urban planning, and I have found nothing implausible about the planes flying into the WTC explaining their collapse, and I have seen the results first-hand of a steel framed building which collapsed after a fire. Yet, even if there were explosives planted to ensure the towers would collapse in a spectacular fashion to make the event more dramatic, it only leads people to something of a dead end, because they then need to answer how the explosives were planted without being detected and who did it.
debunking David Ray Griffin's demolition claims
David Ray Griffin has compiled a list of some of the top claims for demolition. Here are a few rebuttals to the assertions. Tactically, it would be much more helpful to have credible structural engineers and other relevant experts present these claims, instead of theologians. The 9/11 debunkers who support the official story have had much fun pointing to the scanty technical qualifications of the "Scholars for 9/11 Truth" regarding the physical evidence issues -- while ignoring a large volume of evidence that does not require scientific analysis to show the government lied about 9/11.
has a copy of Griffin's list
No large steel-frame building has ever collapsed due to fire. The
official explanation given by the government teams is that fire destroyed
both towers and building 7. The damage from the aircraft and debris are
admitted to have played an insignifcant role.
rebuttal: the WTC did not fall just because of fire. The damage from the aircraft had a major role, it was not "insignificant." The official explanation for WTC7 is the tower falling onto it caused much of the damage, and there are many claims the firefighters knew for hours it was going to collapse. These claims for 7 may (or may not) be true, but ignoring them is not honest.
The collapse of all three buildings occured in a symmetrical, straight
down fashion, into their own footprint. While dust and debris may have
been ejected outwards, the structures essentially fell in on themselves,
leaving surrounding buildings essentially undamaged.
rebuttal: All of the surrounding buildings had gouges in them from the collapses.
The buildings collapsed at almost free-fall speed. This means that
each building must have experienced some spontaneous global structural
failure so that there was no resistance or delay in the collapse. The
official “pancake theory” for the towers is untenable because
as upper floors supposedly collapsed onto those below, there would have
been structural resistance. Instead the collapses began almost instantly
and showed no signs of resistance.
rebuttal: There is no reason to expect the lower floors to substantially slow down 100,000 tons (or more) of material from falling down.
According to the 9/11 Commission, “The interior core of the
buildings was a hollow steel shaft, in which elevators and stairwells
were grouped” (p. 541). In fact, the core of the towers was actually
a support system of 47 massive steel columns. The commission just ignored
these because their existence conflicted with the official story of spontaneous
rebuttal: It would more relevant to examine what the National Institute for Standards and Technology (NIST) said about the core columns, since they did the investigation. Plus, it is reasonable to assume that the plane crash caused considerable damage to the core columns. There were very strong core columns, but technically it is true that the center of the building was hollow (the elevator shafts surrounded by the core columns).
All three buildings were completely destroyed. The resulting piles
of rubble were only a few stories high and there were no large, structural
pieces left. If you consider the structual engineering strength and redundancy
put into the buildings, it is ridiculous to attribute this result to a
“structural failure” or simple “collapse.”
rebuttal: again, there is no reason to assume that the collapse would somehow stop once started.
Nearly all the concrete and non-metallic substances in the towers were
pulverized into a fine powder. The gravitational energy of a simple “collapse”
would not have been sufficient to cause this pulverization.
rebuttal: Controlled demolition is not an explanation for this either, unless you assume each floor was blown up, which is not credible. Some of it may have become ash from the fire.
Molten Steel was also observed by multiple witnesses at ground zero,
even weeks after 9/11. The energy needed to melt steel would only been
possible through the use of explosives or other foreign, high-energy devices.
Jet fuel and the collapse of the buildings could not have created enough
heat or energy to leave molten steel.
rebuttal: controlled demolition does not cause fires for months. Jet fuel was not the only thing that burned in the towers -- paper, furniture, plastic (made from oil), other synthetic combustible materials all added to the conflagration. Strong winds through broken windows and up the elevator shafts turned the towers into chimneys and got hot enough to weaken steel and melt some aluminum pieces of the plane. Perhaps an explanation for the "powder" is "ash" from fire? It would be helpful to ssee primary evidence for "molten steel" (and not molten aluminum from the planes) that can actually be verified.
Firefighters, initial news reports and other witnesses prominently
reported secondary explosions within the towers.
rebuttal: Many have suggested these noises were a combination of very large short circuits and the floors pancaking, which would definitely sound like that. How do you separate the real noises from those sources from the alleged explosions?
WTC 7 housed the New York offices of the CIA, Secret Service, SEC
(Securities and Exchange Commission), and Rudy Giuliani’s Office
of Emergency Management bunker.
The New York Times on WTC 7: “no building like it, a modern, steel-reinforced high-rise, had ever collapsed because of an uncontrolled fire… Because of those doubts, engineers hold open the possibility that the collapse had other explanations, like damage caused by falling debris or another source of heat….A combination of an uncontrolled fire and the structural damage might have been able to bring the building down, some engineers said. But that would not explain steel members in the debris pile that appear to have been partly evaporated in extraordinarily high temperatures, Dr. Barnett said.”
rebuttal: You can't simultaneously have "high temperatures" and claims that the fires weren't hot enough to bring down the buildings. The insinuation that tons of thermite burned for weeks is not credible.
Is There Evidence That Explosive Charges Were Used To Destroy
The World Trade Center Towers?
'ABC News' Special Report:
"Planes crash into World Trade Center"
(8:53 AM ET) Tuesday 11 September 2001
JENNINGS: Well, it may be that something fell off the building. It may be that something has fall--yet we don't know, to be perfectly honest. But that is what you're looking at, the current--that's the scene at this moment at the World Trade Center.
Don Dahler from ABC's "Good Morning America" is down in--in the general vicinity.
Don, can you tell us what has just happened?
DAHLER: Yes, Peter. Don Dahler. I'm four blocks north of the World Trade Center. The second building that was hit by the plane has just completely collapsed. The entire building has just collapsed, as if a demolition team set off--when you see the old demolitions of these old buildings. It folded down on itself, and it's not there any more.
Battalion Seven Chief: "Battalion Seven ... Ladder 15, we've got two isolated pockets of fire. We should be able to knock it down with two lines. Radio that, 78th floor numerous 10-45 Code Ones."
9:52 am from the South Tower - www.thememoryhole.org/911/firefighter-tape-excerpts.htm
[note: the bulk of the fire was above the 80th floor, the 78th floor was at the bottom edge of the fire]
9/11 Survivor Describes Multiple Explosions
>>> Teresa Veliz, the facilities manager for a software development company, was on the 47th floor of the North Tower when Flight 11 hit. First, like many witnesses, she describes the building shaking twice:"I got off [the elevator], turned the corner and opened the door to the ladies' room. I said good morning to a lady sitting at a mirror when the whole building shook. I thought it was an earthquake. Then I heard those banging noises on the other side of the wall. It sounded like someone had cut the elevator cables. It just fell and fell and fell.
I began to cry. "Oh, my God, I just got off that elevator!" I said. "That could have been me." I prayed those other people had gotten off on the 48th floor before the elevator dropped. But I didn't have much time to be upset because the building shook again, this time even more violently. The lady at the mirror grabbed onto me and held on for dear life."
Veliz went down a staircase with a coworker to the concourse level. In the mall, they got onto an up-escalator as the South Tower collapsed, causing a rush of wind which knocked them down. In the pitch black, Veliz and her coworker followed someone carrying a flashlight:"The flashlight led us into Borders bookstore, up an escalator and out to Church Street. There were explosions going off everywhere. I was convinced that there were bombs planted all over the place and someone was sitting at a control panel pushing detonator buttons. I was afraid to go down Church Street toward Broadway, but I had to do it. I ended up on Vesey Street. There was another explosion. And another. I didn't know where to run."
Source: "Teresa Veliz: A Prayer to Die Quickly and Painlessly," in September 11: An Oral History by Dean E. Murphy (Doubleday, 2002), pp 9-15. www.thememoryhole.org/911/veliz-bombs.htm
A Critical Analysis of the Collapse of WTC Towers 1, 2 &
7 From an Explosives and Conventional Demolition Industry Viewpoint
By Brent Blanchard
August 6, 2006
"for explosives to be considered as a primary or supplemental catalyst, one would have to accept that either a) dozens of charges were placed on those exact impact floors in advance and survived the initial violent explosions and 1100+ degree Fahrenheit fires, or b) while the fires were burning, charges were installed undetected throughout the impact floors and wired together, ostensibly by people hiding in the buildings with boxes of explosives. There is no third choice that could adequately explain explosives causing failure at the exact impact points.
"The chemical properties of explosives and their reaction to heat render scenario A scientifically impossible and scenario B remarkably unlikely."
Good Science and 9-11 Demolition Theories
by Mike King
Skyscrapers Then and Now
The World Trade Center towers remained standing immediately after the planes hit because weight no longer borne by damaged columns was transferred to the giant truss on the roof. The subsequent fires eventually weakened the steel in remaining columns and the truss, but the delay in the collapse gave many people -- an estimated 20,000 -- time to escape.
Floor collapses before the buildings fell
"At 9:24, fire rescue received a call from a frightened man who said that the stairway had collapsed on the 105th floor of Tower Two. It would be an omen." - p. 641
"At 9:47, in a nearby office, a woman called fire rescue with an ominous message. The floor underneath her, she said, was beginning to collapse."
James Bamford, "Body of Secrets," (2002 update) p. 64
WTC Pre-Collapse Bowing Debunks 9/11 "Controlled Demolition" Theory
Journal of Engineering Mechanics ASCE, in press
9/13/01, Expanded 9/22/01, Appendices 9/28/01)
Why Did the World Trade Center Collapse?—Simple Analysis
By Zdenek P. Bazant, Fellow ASCE, and Yong Zhou
9-11 Loose Change Second Edition Viewer Guide
And debunking of various 9/11 conspiracy theories
Section III: The World Trade Center
Building to Extremes
February 10th, 2004
Early investigations after September 11th had concluded that the collapse was due to a structural weakness -- that the floor trusses failed, causing the towers to pancake to the ground. But in 2002, the engineering firm Weidlinger Associates came to a different conclusion. Using computer models and sophisticated defense department software, they were attempting to analyze whether the collapse of the south tower contributed to the fall of the other. Engineer Najib Abboud co-authored the analysis.
Najib Abboud: The collapse was initiated through column failures rather than through floor system failures unlike what certain press accounts had surmised in the early days after September 11th. The airplane impacting WTC1, the north tower, was approaching it at about 500 mph. The impact of the airplane remained pretty much central, the airplane continued towards the center of the core. On the south tower, the impact of the airplane was eccentric. It sheared the columns in the corner of the core.
Narrator: Columns throughout both towers were knocked out or broken. Debris from the plane ripped off much of the fire protection on the steel.
Najib Abboud: There is no fire proofing in the world that was ever designed to counter the effects of fragments flying at 500 mile an hour.
Narrator: But still -- the towers stood. The load of the building was transferred via the remaining columns, up to the roof truss.
Najib Abboud: Had the roof truss not existed at all, we believe the collapses would have occurred substantially earlier. That balancing act could have gone on forever had towers did not had to deal with the subsequent fires.
Narrator: These fires, fed by the fuel from the planes, created temperatures as high as seven hundred degrees centigrade.
Najib Abboud: When steel reaches a temperature of around five hundred degrees centigrade at that stage it would have lost half of its load carrying capacity.
Narrator: The columns and the roof truss eventually failed. But the floor trusses -- and the building design -- were not the reason for the collapse. Smoke analysis indicates the floors must have remained intact. On the left, the mass of smoke typically observed when floors are missing. On the right, the differentiated pattern of smoke exhaust and air intake actually observed, floor by floor, at the windows of both towers. The south tower collapsed first, fifty six minutes after it was hit, because it was more unbalanced by the off-center impact of the plane.
Najib Abboud: The north tower outlasted the other one by about twice as much in time. We did prove conclusively that the floors did not contribute and were not the initiating cause, if you will, of the collapses.
April 23rd, 2006 at 9:47 pm *
chicago tom –
Steel doesn’t have to melt in order for it to fail. The fire from the jet fuel burned out in five or ten minutes, but the force of the impact blasted the content of the towers to one side, and ignited it. It was this fire that led to the structural failure.
Both PBS and one of the cable channels did programs on the failure of the towers. The weak point in the structural design was the connecting point between the floor joists and the vertical columns. One end had 5/8? bolts, the other had 3/4?. The heat of the fire caused the floor joists to sag, which caused the undersized bolts to fail. The vertical columns depended on the floor joists for lateral stability — and when they went, the columns blew out.
The tower that was hit last failed first for two reasons — mainly, the plane hit lower in the tower, so there was more weight above the damaged section; the damage was also more off center — when it fell, the upper tower started to tip just before it collapsed.
On Nova, the engineer that designed them said that he knew they were coming down from the moment they were hit — they were not engineered to take that.
On the cable channel (Discovery? History?) they reported that the fireproofing on the structural steel was substandard. It had been replaced up to the 50th floor or so, but the upper floors were essentially unprotected.
Here’s the deal — without fireproofing, ANY piece of structural steel will fail, when exposed to fire. Wood is more structurally fire resistant than steel.
Now — did something weird happen with WTC 7? Maybe; maybe not.
Did the Bush administration ignore the warnings of a pending attack? Absolutely.
Did BushCo cover up the truth after the fact? Absolutely.
But asserting that ‘bombs were planted because the steel didn’t melt’ is seriously unproductive tinfoil territory. The Utah professor is not very helpful either.
Complete 911 Timeline - World Trade Center Investigation
Some 9/11 skeptics who are convinced that the towers were detonated claim that the fires in the buildings had substantially diminished when they fell down. This claim is not supported by looking at photos of the collapses. The South Tower, which had more fuel spray outside the building from the impact than the North Tower, still had substantial fire underway when it fell. In addition, the South Tower had much more weight over the impact zone than the hole in the North Tower.
Note, also, the South Tower did not fall as symmetrically as the North Tower (on the right in the first picture).
The Collapse of the South Tower (hit second, but fell first)
note the South Tower is tipping over on top of the entrance
wound caused by Flight 175,
which is evidence against controlled demolition
from Daniel Hopsicker, "Welcome to Terrorland: Mohamed Atta and the 9-11 Cover-up in Florida" (Mad Cow Press, 2004)
"During his questioning by the FBI, Warrick said he learned details of the attack which the Bureau has chosen not to tell the American people. 'The FBI told me that Marwan almost missed the building. Marwan was flying one hundred miles per hour faster than Atta, they said. And that's why he flew into the building deeper and that's why that building came down first, because there was so much fuel deeper into the building." (p. 305)
If true, the extra speed of Flight 175 would probably have caused more damage to the buildings columns (and this theory is probably vindicated by the fact that there is much more of an "exit hole" for the South Tower than for the North Tower.
The North Tower (hit first, fell second)
fire is all the way across the building in these photos (taken after the South Tower collapse)
South Tower collapse
North Tower moment of collapse -