The infamous liquid ban on airplanes, often mistakenly attributed to heightened security after 9/11, was actually triggered by MI5’s successful disruption of a terror plot in 2006. British intelligence foiled a coordinated plan by terrorists to use liquid explosives disguised as everyday beverages to bring down multiple transatlantic flights simultaneously. The attackers had planned to use acetone peroxide (TATP), a highly volatile and unstable explosive that could be ignited with basic electron