This is another contemporary copy of this photograph, which for many years was thought to the be the last view of the St. Francis Dam intact (until this one showed up).

We've seen "original" glossy prints of this image in three or four different places, suggesting it was mass produced as a souvenir after the dam broke on the night of March 12, 1928. This 2½x4-inch print was purchased, with others, at a flea market — so we don't know the circumstances of its existence — and there are duplicates of it in this "flea market" grouping, with slightly different exposures.

Construction on the 600-foot-long, 185-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 411 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.