I remember when I first saw them fall I told my coworker that I think it might come out that a controlled explosion was triggered to protect the surrounding buildings. Maybe these charges are in place in other buildings, just in case. A secret like that would probably also be covered up. I heard an accepted explanation is that the momentum of the upper floors falling down - having their moorings molten by the aircraft fuel fire - caused every floor below to continue crashing straight downward. The tower that was not hit? Good question. Maybe the shock waves to its foundation affected it like with the hotel in Florida. Do you know where these non-conspiracy theories have been discussed? I have to remind myself that these are not toy or model sized towers whose weight is far outmatched by the strength of the material they are built with. The question is, do the physics formulae involved calculate to cause this result.