http://cryptome.org/info/wtc-punch/wtc-punch.htm
Aircraft Wheel Punches Out a Steel Wall Section of WTC Tower
John Young, Cryptome
An intriguing record of the WTC attack on 9/11, at least for this architect, are the photos (below) showing a 3-story section of the exterior wall of one of the Twin Towers -- probably the North (hit first) -- with an aircraft wheel embedded in a window opening. The site was covered by the towers' collapse and it is not clear what happened to the ensemble.
This is an astonishing fragment which shows the power of a high-speed rubber projectile to punch a two-ton lattice of steel framing out of its setting. Then the ensemble rockets in an arc about 700 feet south over the 12-story Marriott Hotel and about 900 feet down, to land almost horizontal on an empty lot, curb and street. (There could have been other aircraft parts aiding this launch but they are not visible at the scene.)
How the 500-mile-per-hour wheel rocketed from the north wall penetration, across the north open offices, past the core services of elevators, stairs and utilities and large steel columns and bracing, then across the south open offices, some 200 feet of gauntlet, and still maintain sufficient momentum to drive the wall section into a quarter-mile arc, is to be fearfully imagined.
(And added by moderator from deleted post)
52 Photos of WTC7 collapse
wtc-nist-wtc7.zip 52 Photos of World Trade Center 7 Collapse March 13, 2010 (37MB)
Includes photos showing damage to WTC 7 from parts of the tower falling on, plus several photos of fire on various floors of WTC 7