Haven't seen this yet so i'll be the faggot to post it.

Think Kursk sub and it's missile tubes filled with expanding foam when you think Pentagon.

Was it a "Granit"?

Who knows, but here's 1100 pages worth looking at.

https://www.scribd.com/document/170266922/9-11thology-The-third-truth-about-9-11-or-Defending-the-US-Government-which-has-only-the-first-two