Al Capone. George "Machine Gun" Kelly. Alvin "Creepy" Karpis. These are some of the infamous criminals who once called "The Rock" home.
Even though Alcatraz closed 50 years ago, the prison on an isolated island in the middle of San Francisco Bay remains the foremost symbol of criminal justice in the first half of the 20th century. It is a relic forever tied to an era of gangsters and organized crime that fascinates generations of people born well after the last prisoner was transferred off the island. Alcatraz's closure 50 years ago today essentially ended that era, but the legendary stories from within the prison's concrete walls continue to draw nearly 1.5 million visitors every year.
In honor of this anniversary, take a step back in time with photos from the prison's heyday.
Alcatraz Island and its penitentiary are seen in San Francisco Bay from the air in the 1930s. (AP)
From left to right are the laundry room, power plant and quartermaster building on Alcatraz Island on Oct. 20, 1933. (Ernest King/AP)
San Francisco Police Chief William J. Quinn, Warden James A. Johnston, U.S. Attorney General Homer S. Cummings and San Francisco Mayor Angelo Rossi inspect a new cell block in the main building on Alcatraz Island on August 20, 1934. (AP)
Al Capone, Chicago's infamous gang overlord during prohibition, is released on Nov. 16, 1939, after 4 1/2 years behind bars at Alcatraz. (AP)
A guard locks the solid metal sliding door of one of the solitary confinement cells on April 18, 1941. (AP)
Warden James A. Johnston looks into a cell where rioting convicts held several guards hostage before shooting them on May 5, 1946. (AP)
The prison hospital's operating room is shown through the glass of a locked door on March 13, 1956. (Ernest K. Bennett/AP)
Alcatraz is shown on June 12, 1962, the day three prisoners escaped. (AP)
This air vent was used by three convicts to escape from the main prison building on June 12, 1962. The three men were never found. (Alcatraz Federal Penitentiary/AP)
A line of handcuffed prisoners, the last of the convicts held at Alcatraz, walk through the cell block as they are transferred to other prisons on March 21, 1963. (AP)
Want to see more? Check out a full photo gallery of "The Rock" here.