65. The Tragic Collapse of the St. Francis Dam

Year: 1928

Location: Los Angeles, California, USA

Company: Los Angeles Department of Water and Power

Estimated Damage Value: $7 million*

In 1928, the St. Francis Dam disaster in Los Angeles marked one of the worst civil engineering failures in American history, claiming over 400 lives and destroying vast farmlands. The disaster ended William Mulholland’s career and caused $7 million in damages.

The Mulholland Dam lacked essential contraction joints, leading to crack formation. Despite personal inspections by Mulholland dismissing concerns, the dam catastrophically failed on March 12, 1928, releasing 12.4 billion gallons of water, erasing evidence and taking lives.