Why Indeed Did the WTC Buildings Collapse?

In writing this paper, I call for a serious investigation of the hypothesis that WTC 7 and the Twin Towers were brought down, not just by impact damage and fires, but through the use of pre-positioned cutter-charges. I consider the official FEMA, NIST, and 9-11 Commission reports that fires plus impact damage alone caused complete collapses of all three buildings. And I present evidence for the controlled-demolition hypothesis, which is suggested by the available data, testable and falsifiable, and yet has not been analyzed in any of the reports funded by the US government. We start with the fact that large quantities of molten metal were observed in basement areas under rubble piles of all three buildings: the Twin Towers and WTC7. A video clip provides eye-witness evidence regarding this metal at ground zero:. The photograph below by Frank Silecchia shows a chunk of the hot metal being removed from the North Tower rubble about eight weeks after 9-11. Notice the color of the lower portion of the extracted metal — this tells us much about the temperature of the metal and provides important clues regarding its composition, as we shall see