Two men pose with the wreckage of a steel-truss bridge that has been destroyed in the St. Francis Dam Disaster of March 12-13, 1928.

A copy of this photograph resides among the Charles H. Lee papers at the U.C. Riverside Library, where a description reads: "Two unidentified men posing with a large metal structure damaged by the collapse of the St. Francis Dam." The photographer and location (other than Santa Clara River Valley) are evidently unknown.

This could be either an auto bridge or a train bridge seen on this map.

Seven miles up San Francisquito Canyon Road from today's Copper Hill Drive, construction on the 700-foot-long, 205-foot-high St. Francis Dam started in August 1924. With a 12.5 billion-gallon capacity, the reservoir began to fill with water on March 1, 1926. It was completed two months later.

At 11:57:30 p.m. on March 12, 1928, the dam failed, sending a 180-foot-high wall of water crashing down San Francisquito Canyon. An estimated 431 people lay dead by the time the floodwaters reached the Pacific Ocean south of Ventura 5½ hours later.

It was the second-worst disaster in California history, after the great San Francisco earthquake and fire of 1906, in terms of lives lost — and America's worst civil engineering failure of the 20th Century.