What today’s Supermax prisons accomplish with round-the-clock electronic surveillance of every sort, Alcatraz did by virtue of its location. Located just 1.5 miles from mainland San Francisco, but that 1.5 miles is made of frigid waters, treacherous currents, and sharks. Even a prisoner who managed to get outside the walls of the prison would still have to negotiate forces that could overcome the hardiest. When it closed, it was due to finances, and not its security.

On this day, March 21, 1963, the last of the prisoners from “The Rock” were transferred to a replacement maximum security facility in Illionois. Alcatraz the prison became Alcatraz the museum.

Alcatraz housed the most famous criminals – Al Capone, “Whitey” Bulger, “Machine Gun” Kelly – but they were relatively trouble-free. It was the quiet inmates who attempted escape. One of the most intricate came in 1962 when a trio of inmates escaped via a chiseled-out tunnel they made through the water-softened wall. They dug during music hour so the noise would be masked, and placed a false wall to conceal the the hole. Once out, the men boarded a makeshift raft they constructed and headed to San Francisco Bay. It is not known if they made it – some of their equipment was discovered on a nearby island, but the men themselves were never seen or heard from again.