Trump says Alcatraz, now part of the National Park Service, suddenly is needed to house America’s “most ruthless and violent” criminals. It's where the government sent notorious gangsters Al Capone and George “Machine Gun” Kelly as well as lesser-known men who were considered too dangerous to lock up elsewhere.

Located on a lonely island in the middle of San Francisco Bay, Alcatraz was as much a psychological prison as it was a physical one.