A section of the St. Francis Dam, known as the "tombstone" or the "monument," remained standing after the dam broke on the night of
March 12, 1928. It was located 7.2 miles up San Francisquito Canyon Road from today's Copper Hill Drive in Santa Clarita.
This north-facing photograph was shot by Hetta Laurena Carter a few weeks after the dam break.
In front (south) of the tombstone is the section that had stood to the (viewer's) left of it.
Further reading: Failing St. Francis: Water Pressure or Political Pressure?
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 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.