@romin I was only referring to the twin towers, which were 2 buildings.

Yes, that's what generally happens when poorly designed buildings burn for long enough.

I found this report as to why the building collapsed and I'm sure you'll be able to point out why the conclusion reached are wrong: https://www.govinfo.gov/content/pkg/GOVPUB-C13-4d4c17460292ee57ef313f6491fa8d1e/pdf/GOVPUB-C13-4d4c17460292ee57ef313f6491fa8d1e.pdf


If I was the US government doing 9/11, I wouldn't have bothered to intentionally take out more than the twin towers at the WTC, as that would needlessly complicate the plan.