Constructed in 1926, and failed in 1928, the St. Francis Dam, formerly located here, killed between 400 to 500 people as floodwaters tore through San Francesquito canyon, the Santa Clarita valley, Fillmore, Santa Paula, and Ventura.
Pieces of the old dam can clearly be seen in this imagery here, and further downstream.
see www.youtube.com/watch?v=BilO_Bv7pW0