Well, hoping we can finally stamp "Busted" (a 'la Mythbusters) on the controlled demo theory:
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Quote from:
http://quote.bloomberg.com/apps/news?pid=10000087&sid=aCuh.ATdfOXc&refer=top_world_news
Buckling Steel
According to Shyam-Sunder, the concave bowing of the steel was seen on the sides of the towers opposite where the planes hit them. At 10:06 a.m. that morning, an officer in a police helicopter reported that ``it's not going to take long before the north tower comes down.'' This was 20 minutes before it collapsed. In another radio transmission at 10:21 a.m., the officer said he saw buckling in the north tower's southern face, Shyam-Sunder said.
The report includes photographs taken from police helicopters showing the bending columns.
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If explosives were used, the Towers wouldn't show signs of Buckling 20 minutes before hand. Can we get further info on it? and pics, if the report is available.