Explosives Found in World Trade Center Dust http://theintelhub.com/2011/02/06/explosives-found-in-world-trade-center-dust/

For Dr. Niels Harrit, nanotechnology expert and a recently retired University of Copenhagen chemistry professor, it all began when he watched the collapse of the World Trade Center’s Building 7. Harrit watched it come down in amazement, noting, “I had to watch it again… and again. I hit the button 10 times and my jaw dropped lower and lower.”

The 47-storey structure, with a base the size of a football field, was not hit by a plane, but collapsed at free-fall speed seven hours after the Twin Towers, at 5:20 PM. “I had never heard of that building before and there was no visible reason why it should collapse in that way. Straight down, in 6.5 seconds. I have had no rest since that day,” Harrit says.