Unlike the "beautyshot" front view, the rear view of falling building 7 isn't nearly so neat.
This is a detail from one of the NiftyThings.org videos, down now and archived at
http://thewebfairy.com/wget/www.niftythings.org/usattack/videos
It's the one with the perky reporter
talking to a mother with a baby while a glow overtakes the scene and then the
building falls.
The camera is pointed in that direction, but this omnious glow was not seen
by the cameraman.
This file is from a corner of the background.