Alcatraz began its working life as a fortress but the fact that it was cut off from civilization by the bay's freezing waters and strong currents convinced the military to convert it to a stockade.
Alcatraz became a federal prison in 1934 as crime surged during Prohibition and the Depression.
It only housed around 300 prisoners at any given time, and only the worst of the lot: Al Capone and George "Machine Gun" Kelly both did time on The Rock.
An interesting sidelight: Alcatraz was the only federal prison at the time that provided hot-water showers for its inmates, but the motivation was hardly humanitarian.
Prisoners used to hot-water showers, the reasoning went, would find the frigid waters of San Francisco Bay almost impossible to withstand during an escape attempt.
It must have worked. There is no record of a successful escape ever being made.
Of the 36 inmates who tried, 23 were recaptured, six were shot and killed, and two were confirmed drowned. The other five were never heard from again and are officially listed as "missing and presumed drowned."
SOURCE: nuttyfacts
