Someone I knew, Alan Beavan was on Flight 93 that went down on 911, so every anniversary I usually watch some of the documentaries on it. I don't know why. Obviously it was planned, so the idea tjat accelerants like thermite may have been planted in target areas is not out of the question, and maybe even likely. But the planes were made out of aluminum, so I wonder if that may have produced a similar effect. Also, a gaping hole in a building 1,500 feet above the ground may produce a wind tunnel blast furnace effect, especially with the hollow elevator shafts. In any case, the iron and steel did not need to melt to lose its strength and result in the buildings pancaking down. Also the energy of the two buildings collapsing must have been incredibly high, causing iron to melt. None of those images of molten metal surprise me at all give what happened. Another possibility is magnesium may have been in the plane or building material. That alone would cause temperatures twice as hot as needed to melt iron or steel.