I'm ready for building 7 too:Yeah apart from building 7 that was clearly brought down with explosives.
There was no sound of explosion before the building came down - watch some real ones, the explosions are really loud.
The building started collapsing at the top, then you could see damage at the centre, before the base gave way and it fell.
The building was on fire for hours before it fell, and no firefighters were available to slow the fire.