New Incriminating Implosion Footage 9/11

Another angle of Building 7, showing a vertical line of windows being blown (several floors worth) just before the collapse. (You can see yet another line of windows blown in "911 Mysteries" -- Building 7 section.) Continue on to watch the core columns of the North Tower revealed as the exterior is destroyed. The question to official sources: If it's a "pancake collapse" -- floor by floor, each floor smashing down on the next -- why does the core last to the very end? Oh, yes! It's because the core was in a hollow shaft, and there were no "floors" to come down on it, but then why does it too give up and turn to dust in less than half a minute?