Watch the force of this video. Watch the ferocity of the following explosion. Frankly its amazing the stood as long as they did.
http://www.metacafe.com/watch/31999/rare_sep_11_clip/
Those who talk about demolition watch this clip.
http://www.metacafe.com/watch/134744...loor_explodes/
Notice where the fall begins. At the break point where the plane hit. The top just starts to come down. This is so obvious that its amazing there is still debate going on.