This 12 second clip was taken from a 1:02 hour long video that was posted on YouTube. After a few viewings, we noticed the flashes cascading down the building.
This video shows first, the 12 seconds in real time speed, then is slowed down to half speed for a 26 second viewing. This clip was not edited or altered in anyway, besides slowing down the speed in the second half of the clip.
There is much debate about the cause of the collapse. We thought this particular excerpt may shed more light to what happened that day at the World Trade Center.