Possible Duplicate:
On 9/11, was Building 7 destroyed in a controlled explosion?
Having just watched the movie Zeitgeist, I'm a bit unsettled because I don't know how to refute the idea that the Twin Towers collapsed in a way that's inconsistent with known physics.
Specifically it bothers me that the buildings had steel superstructures which it's claimed couldn't possibly have gotten hot enough to melt. If that's so, why did they not remain standing even when the supported floors collapsed?
NEXT DAY...
I don't have the rep to delete my own question here. But this other question, although primarily about Building 7, has very good answers covering everything I wanted to know. My apologies if anyone feels I have wasted their time asking again.