explosion detonation world trade center
Recently, the International Center for 9/11 Studies has released a new set of videos, kept before by the NIST and formerly possessed by the FBI.
In one of them, some detonations seem to be heard during the collapse of the South Tower. One witness even spoke about "explosions" at the end of the video.
The readers of 911blogger could be interested. Take a look and use some earphones to listen carefully the soundtrack:
For the first time, the full video is also online :