A bridge nicknamed 'Galloping Gertie' tore itself apart in a light wind
The Tacoma Narrows Bridge opened in July 1940 already famous for swaying and bouncing in modest winds, earning its nickname. Four months later, a 40 mph wind triggered a twisting resonance engineers hadn't accounted for, and the deck oscillated wildly until the bridge ripped apart. The collapse was filmed in detail and became the standard case study that reshaped how engineers design for aerodynamic flutter.