Home to the nation’s first supermax prison, Alcatraz was said to be impossible to escape, separated from San Francisco by 1.5 miles of cold, inhospitable waters. Much of its intrigue to visitors comes from the legends of the infamous criminals held within its confines between 1933 and 1963, including Chicago crime boss Al Capone, the Birdman of Alcatraz Robert Franklin Stroud, Alvin “Creepy” Karpis, and George “Machine Gun” Kelly.