Alcatraz Island

The massive, concrete cell block rising from the center of the island is the dominant feature of Alcatraz. Once a military fortification, the site transitioned into a federal penitentiary that operated from nineteen thirty-four to nineteen sixty-three. Its location in the middle of the San Francisco Bay, surrounded by cold, fast-moving currents, made it a natural choice for isolating the most difficult prisoners in the federal system.