This thread will be a little different than any other I've ever seen. Most arguments against the official story of 9/11 do not seem to understand that you can not win an argument against an opponent who is claiming incompetence in place of bad intention. Also, it can not easily be shown that the construction of the towers(and building 7) would fall or not fall in any certain way, given the complexities of engineering and the plethora of unknown materials/conditions which could have been innocently present within the building at the time of collapse. So, I've decided to refine my argument a bit, and only concentrate on the evidence which can not be accounted for simply by bad construction/engineering and a clever imagination. So, with crappy construction being a given: I've been focused on one aspect of the collapses lately- the billowing clouds. Where did they come from? What mechanism can account for the quantity of clouds seen, before the debris even hit the ground? How quickly should the fires have been extinguished from the collapse itself, especially given all the suffocating pulverized concrete saturating the air. In certain videos, during the collapses of the towers you can see an ejection of thick clouds below the main debris, floor by floor, leading the collapses. Are these billowing explosions the result of just the pancaking of floors? Can the pancake effect really cause 90% of the buildings' concrete to instantly pulverize. Why does every piece of the collapsing building seem to disintegrate in mid-air, leaving a trail of itself all the way down? How does a skyscraper turn from a rigid steel and concrete structure, to a puff of billowing clouds in only a few seconds? Also, where are the Pentagon surveillance videos of the plane hitting?