This footage was shown by the BBC in a programme "9/11:The Twin Towers", broadcast in the UK on 7 September 2006. The sound of the ... all » demolition charges used to bring down the WTC South Tower can clearly be heard. The sound has not been enhanced in any way and accords precisely with the eye witness testimony on 9/11, including that of the FDNY fire-fighters. The building had 114 floors, but took only 10 seconds to collapse. Fourteen of the explosions can be heard in a period of 5 seconds, so the blasts cannot have been generated by collapsing floors (the so-called 'pancake' effect), or the collapse of the entire building would have required more than 40 seconds!