Why Did World Trade Center 7 Collapse? Gerald Posner Breaks It Down | The Brief

“Jet fuel can’t melt steel beams” became one of the most famous claims in 9/11 conspiracy culture. But did the steel need to melt for the towers — or World Trade Center 7 — to collapse?

In this highlight from The Brief, Gerald Posner explains the engineering argument behind the World Trade Center collapses, including why steel can lose strength or expand from heat long before it melts, how fireproofing mattered in the Twin Towers, and why investigators concluded that uncontrolled fires and structural failure brought down WTC 7.