Professor Steven Jones presenting his X-ray spectrometry evidence from samples taken at the WTC site. They dramatically show a PERFECT MATCH for the highly specialized compound "thermate" (used for cutting through steel) found in the WTC debris. (And no, thermate was NOT used during the clean up operation...this stuff was in the building, and ignited, prior to collapse.) If you're new to this information, you might want to check out "Molten Metal" and "Fire Initiated Collapse - Primary Arguments Against"
These "previously molten spheres" consist mainly of IRON (which, to melt, requires temperatures that far exceed anything jet fuel or burning office materials could produce.)