"The official explanation is that ordinary fires were the main reason for the collapse of Tower 7. That makes this the first and only tall skyscraper in the world to have collapsed because of fire. Yet despite that all the thousands of tonnes of steel from the building were carted away and melted down."
"Avery points out that Tower 7 housed some unusual tenants: the CIA, the Secret Service, the Pentagon and the very agency meant to deal with disasters or terrorist attacks in New York - the Office of Emergency Management."
I didn't realise so many people, in the States, felt that Bush and his government were hiding something over the attacks (53% according to the New York Times) or that a third of another poll believed that government officials either assisted or allowed the attacks to take place.
Anyway, here's the BBC's article:
The Evolution of a Conspiracy Theory (BBC Online; Friday 4th July 2008)