The Iroquois Theater: Panic HardwareA tragic crush that created the everyday push bar.

From the show

Rules Written in Blood

Architectural engineering must account for the reality of human psychology during emergencies. In 1903, hundreds perished when a surging crowd pressed against inward-opening doors, sealing themselves inside a burning building. This catastrophic failure of infrastructure led a hardware salesman to co-invent a mechanism that operates seamlessly under blind physical pressure. Modern exit mechanisms exist solely because of this chilling lesson in crowd dynamics.