Joining in the 9/11 debate, no steel structure in history has even collapsed due to office fires. The Twin Towers shouldn't have collapsed due to the planes hitting them. The heat of the engine oil cannot become hot enough to melt the steel. This is interesting, as WTC5 collapsed on it's own without a plane hitting it. Also, looking at how the buildings fell - they all fell from a complete standstill to complete flat within 10 seconds ish. Without dynamite as aid, this cannot be achieved. The idea that momentum increased as each floor collapsed on the next is preposterous, these buildings were designed not to be melted by fire.
Also, other FBI buildings were randomly destroyed and these were given little air time. Coincidence?
Other factors as well are important, such as when the plane landed near the Pentagon, the CCTV of the shop across the road from it had their CCTV confiscated before they could look at it... Do they have something to hide? I think so... Probably because the official 'footage' was edited...