Regarding the picture Bob provided here, if we analyze it we should apply Occam's Razor in that analysis. What does the photo show? It shows an event NOT caused by what NIST said caused it. That is, that result was NOT caused by burning office furnishings and jetfuel fires and gravity. Occam says the simplest explanation is usually the correct explanation. The reason it looks like some sort of small nuclear bomb went off is because indeed, some sort of nuclear bomb went off. The pulverized concrete, mixed with the by-products of the thermite reaction, covered much of lower Manhattan, in some places as thick as 4 inches deep. Thank you Occam.