In 2018, Italy’s Morandi Bridge collapsed, killing 43 people. For 50 years, the iconic bridge had withstood the elements—and stress from ever-increasing traffic. NOVA investigates what went wrong and explores other bridge collapses across the United States. How can new engineering techniques make bridges safer and prevent such tragedies?

Originally released by PBS, 2019. Streaming video file encoded with permission for digital streaming by Infobase on September 24, 2019.

Dangerous Bridges (2:19); --Morandi Bridge Collapse (5:03); -- Disaster Rescue (2:17); -- Structurally Deficient Bridges (2:06); -- Ponte Morandi Inquiry (4:37); -- Origin of Failure (3:20); -- Traffic Loads (5:50); -- Single Point Failure (5:40); -- Steel and Concrete (7:30); -- Bridge Maintenance (5:49); -- Aging Infrastructure (2:49); -- City of Bridges (4:28); -- Credits: Why Bridges Collapse (0:51); .