Santa Clarita, California
The Santa Clarita Valley was the scene of the second most deadly disaster in Californian history, behind the 1906 San Francisco earthquake. It was known as the "worst civil engineering failure of the 20th century". Before midnight on March 12, 1928, the St. Francis Dam collapsed. It caused a flood to rush all the way West to the Pacific Ocean near Ventura. An estimated 431 people were killed, and the site of the present-day Westfield Valencia Town Center was buried in muck. The disaster resulted in the end of the career of engineer William Mulholland.