I saw it. Did you? WTDF, dude can you hear yourself? Walked into steel tube buildings by eyeball, from the planes at 500 mph..
What folks don't understand is the fire didn't burn thru the floors below the Mulit-floor damage Zone.
Now in that zone, introduce jet fuel and powdering aluminum and powdering steel. BOOOOOM.
I saw it. Both time. Many floors. So, what is also in those floor? This gets ignored. It was full of fuels and flammables now doused in Jet fuel, in a instant thermite like mixture areosol. Add more OOOO. BOOOOOOOOOOOM. Paper and Plastic.
Now this mutifloor fire of not much jet fuel anymore but megatons of office wood and plastic coated like a disk drive platter with thermite-like mist.
Hell.
This heat doesn't burn steel, but a steel beam will sag like spaghetti. Those floor above began to come down and feed the fire and sagging more beams and getting more weight on undamaged floor below, plus the water from the extinguishers.
The outer load structure limit was exceeded finally, by all those intact floors above.
So, almost all of us know this. Why don't you?