Well, not really. We didn't entirely know it woudl happen, but my AP History teacher was telling us conspiracies about it.
He told us how the Tower 7, part of the World Trade Center was damaged by the crash, and 2-4 days later it randomly crashes down on itself.
Though, another one that I find interested was that there was a letter on Bush's desk when he was in Office, 1 month before 9/11, and it was from the CIA saying how they think Terrorists are going to be flying planes. Happened 1 month after that letter. Kind of odd, but I don't know more than that. Though, it's true about the letter.