Cant be sure, and I dont go around trying to tell people it was, because I dont have any real evididence and dont want to disrespect those that died or got sock afterwards. There was a single video out of a ton tbat i watched back in the day that had some interesting points. Unfortuntaly that video I've never been able to find again, must have got taken down and well thats that I guess. It showed other buildings having "pancake collapses" and they all slowed down as the fell and then tipped over after a few floors. They weren't as big as the TT obviously byba long shot, but there was a bunch of them and they all did the same thing, one floor busted into the next, then the weight would wreck the next floor and then the next floor would go a short time later and the next and then it would start to tip, every time the same way. The same video showed "real time" footage of the towers falling with a timer on the screen, and they fell faster than an object dropped from the top would have taken to get to the ground, I never did the math myself using any of the many vudeos of the attack, but it wouldnt be hard to do. Also every controlled demolition ever looks exactly like the way those buildings dropped. This is in no way conclusive evidence, and I'm not a conspiracy nut, but it still made me think.