I saw it as well...
An interesting note was that the fire did not MELT the trusses as many people think, however, they only weakened from the heat.
Also, the trusses didn't collapse, they mereley sagged and popped off the mounting points where thy connected to the exterior frame.
Interesting note about the stairwell that was completly unobstructed- short of smoke- because it was routed around some elevator machinary at the same level the plane hit.
Even the sadder that so many more people could have lived had they only found that stairwell A.
MrPex
MrPex