|Boom boom boom boom boom
For whatever reason, some folks are still arguing over whether or not explosions preceded the 'collapses' of the twin towers, even though the evidence is plentiful.
back at the firehouse
This video is from the Naudet DVD; it was recorded on 9/11/01. In it, men in FDNY uniform clearly state: "Floor by floor it started popping out... -- It was as if they had detonated -- as if they were planning to take down a building, boom boom boom boom boom... all the way down." (download video)
There's also this video of an FDNY man referring to the "explosions and then the subsequent collapses".
There's also this audio which makes multiple references to the "secondary" explosions long after the buildings were hit.
There's also this audio which makes multiple references to "explosions" from devices in the building.
There's also this video of a Port Authority Inspector answering a question about crashes, explosions, and collapses. It also gives us a good look at widely-separated explosions in WTC1 occurring siumltaneously just as the WTC2 fireball erupts!