Notice the hole in the roof of building 6.
That actually goes down 9 upper floors and 10 basement floors down and the debris field, indicates an explosion up from the bottom out of the hole, not in through the roof downwards, as the official story states for why it looks like it does?
The explosion, from the bomb in building 6, could be felt in the subway stations on the other side of the WTC complex.
It was also on fire, before the first plane hit, with several fire crews already there.