When those jets hit, the twin towers literally got their bells rung. Big time. The shock wave rang down through the entire support structures causing considerable damage all the way to sub-levels. Marble tiles on the walls of the ground level and skylobbies were knocked off the walls, elevator openings and office doors in floors far below the impact zone were twisted or jammed. The fuel explosion blasted down elevator shafts, blowing out the huge plate glass windows in the ground floor lobbies, and starting some small fires. Some people in elevators were burned to death, elevator cables were severed, sending the cars into freefall down the shafts. Those in them were saved by the auto-braking system.

When those jets hit, the twin towers literally got their bells rung. Big time. The shock wave rang down through the entire support structures causing considerable damage all the way to sub-levels. Marble tiles on the walls of the ground level and skylobbies were knocked off the walls, elevator openings and office doors in floors far below the impact zone were twisted or jammed. The fuel explosion blasted down elevator shafts, blowing out the huge plate glass windows in the ground floor lobbies, and starting some small fires. Some people in elevators were burned to death, elevator cables were severed, sending the cars into freefall down the shafts. Those in them were saved by the auto-braking system.

A female PAPD officer on the fifth sub-level rescued several people from a partially open elevator that was on fire.

When firefighters entered the lobby of the North Tower, their videographer refused to film the people there on fire.

One guy in his office on the 40th floor of the South Tower said that, although he had no clue what had happened, he felt the building violently twist or torque left and, sitting in his office chair, was slammed hard against the wall. He got the hell out there tout suite.

North Tower damage assessment:

The impact force of a 130 ton jet flying at or near 500 mph, calculated in Joules or Newtons, is equivalent to the detonation of .75 tons of TNT. Helluva blast.

The B-767 struck the North Tower almost dead center, easily penetrating the perimeter wall and 70 feet of floor space before smashing broadside into the core structure. The heaviest parts of the jet, the fuselage and engines penetrated the core, and the heaviest section of the fuselage exited the south face.

There is no question the damage to the support structure was severe. Support columns were severed, bent, twisted, buckled, or otherwise compromised, and critically, the damage was sufficient to trap 900 to 1000 people with no survivable means of escape.

9/11 truthers try to tell us the fires were insignificant, or relatively benign.
FDNY has a decidedly different opinion, as did over 200 people who chose the non-survivable means to escape the smoke, heat and flames.

Truthers say, "Jet fuel cannot melt steel."
No shit, Sherlock, jet fuel burns at 1400F, steel melts at 2400F. At 600F, steel begins to weaken, at 1200F, steel loses 50% of its strength. Temperatures in the twin tower spaces reached 1800F, same temp that sets conditions for a flash over. Been there, done that.

Firefighters use the term "Fuel Load" which is a calculation of the volume of combustibles in a closed or compartmentalized space - like an office. The offices in the towers were loaded with combustibles - paper, cardboard, wood, plastic (tons of it), rubber, fabric, oils and grease, alcohol, propane, butane, booze, you name it.

Those unfortunate people trapped in the North Tower made or received over 3000 phone calls. They called 911, family, friends, associates, and received calls from same. As horrifying as their circumstance were, one guy's phone calls to his wife, friend and to 911 are telling.

Called his wife first, no one home, called a friend, got in touch, traded calls with him. Then he called the 911 dispatcher. Told her he and a woman colleague were trapped in their office, debris had crashed down against the office doors and they were unable to get out. He said they were okay, they would sit tight and wait for rescue, but to please hurry. Then he called an NY CBS affiliate with an appeal, the TV anchor put him on the air.

This fella told whoever was watching CBS that he and his colleague were trapped in their office and there was no freaking way out. Floors had collapsed around them bringing smoke, dust and debris, steel and concrete rubble blocked the doors, and part of the core was missing.

Did you get that? PART OF THE CORE WAS MISSING, and his office was on the 86th floor, 9 floors BELOW the center of the jet impact zone and 7 floors BELOW the lowest floor hit.

OK, now I'm gonna speculate, but rather than making any observations fit a personal agenda, I'm gonna do it like a true truther should and apply the laws of logic and reason to what we have heard about the damage from the observer on the scene.

We can surmise that when that bad boy slammed through the tower, it not only damaged what it hit, but it kicked loose one hell of a concrete and steel cascade, and a large volume of it crashed all the way down through 9 floors and got that young fella and the woman with him killed. They didn't make it out.
No firefighters, 1st responders, paramedic units, or rescue squads made it to the 86th floor.

So, let's take into account that the damage to the tower's support structure was, in a word, extensive.

And talk about Fire, and fires

I'll skip the lectures on fire science, the hows and whys and wheres that fires burn,
and how to fight them. Other than to say, an uncontrolled fire has a mind of its own.
Those babies are friggin dangerous.

So, I'll focus on how fires affect the things they burn, like metals, like steel.

When steel is heated, thermal expansion occurs.
When heat is applied to a steel beam, even a portion of it,
the steel expands in all directions. The beam will get longer and fatter.
However, a structural steel column bearing a load cannot expand on its longitudinal axis,
IOW, it's too weak to lift the load.
So, it warps, it bends, even buckles, it's longitudinal load axis is considerably weakened.
There is no point in remapping the most accurate estimates of support columns affected by the crash,
over my ten years here, I've covered this countless times.

I'll begin with a verifiable premise.
In both the South and North towers the initial structural failure precipitating the collapse occurred in the jet impact zone, right where the damage was greatest and the fires the hottest.

No detonation of explosive devices caused the failures, simply because no explosive device, devices, or firing circuits could have survived the jet crash and fuel explosion.

Occam's Razor - the simplest explanation is most likely the correct explanation.

Gravity and mass in motion and mass at rest are the dynamics of a building collapse.
Gravity being the workhorse. Any demolition engineer knows that.

The damaged columns in both tower's core were heated, one by one, two by two,
beyond any hope of bearing a load, and their share of the load was handed to the remaining "healthy" columns,
after enough of the hot damaged columns had failed, the axis of the load bearing stress on the healthy columns was no longer vertical, they were bending toward the weak spot. And they eventually broke. And down came Humpty Dumpty.

In other words, folks, the WTC towers collapsed due to severe structural damage further weakened to collapse by heat.

One other thing, for the record,
It wasn't the Israelis, the Mossad, the CIA,
or little green men with laser weapons,
or something conjured up by cowboy Bush
that attacked us on 9/11.
Al Qaeda terrorists attacked us on 9/11.
That was seminal moment for Islamic terrorism,
Islam had a new face, and it isn't pretty,
caused a paradigm shift in geo-politics.

As for the neo-Nazi Whole2th, he can kiss my ass.