Fifty years ago in the Los Angeles neighborhood of Baldwin Hills a tiny crack in the wall of the Baldwin Hills Reservoir became a 75-foot-wide breach that allowed more than 250 million gallons of water to burst free in a killer wave. The reservoir had been built on an active geologic fault, a fact that was known by engineers but deemed unimportant. The images above and below, part of the Los Angeles Public Library’s collection of vintage L.A. photos, show the beginning and aftermath of the event. The first shot was taken as workers were examining the growing crack. At some point, a shouted warning sent them scattering and the dam broke. The time elapsed between the discovery of the crack and the failure of the dam was about three hours. No workers were hurt, but within the path of the wave, an area roughly bounded by La Brea Avenue, Jefferson Boulevard, and La Cienega Boulevard, five people were killed, sixty-five houses were completely destroyed, and 210 other residences were damaged. That was today in 1963.