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A National Park Service ranger walks dow

A National Park Service ranger walks down "Broadway" in the main cell block on Alcatraz Island, 14 June 2007 in San Francisco Bay of California. Sometimes referred to as "The Rock", the island of Alcatraz served first as a military fortification, before it became a federal penitentiary in 1934. Now Alcatraz is national recreation area under the supervision of the Naitonal Park Service (NPS) with more than a million visitors a year taking the short ferry ride from San Francisco's Fisherman's Wharf to experience the infamous maximum-security prison for high-risk convicts. Famous island residents have included "Machine Gun" Kelly, Al Capone and Robert "Birdman" Stroud. AFP PHOTO / Robyn BECK (Photo credit should read ROBYN BECK/AFP/Getty Images)

Alcatraz marks 50th anniversary

The National Park Service celebrated the 50th anniversary of Alcatraz Island's closure as a federal penitentiary on March 21 with an exhibit of newly discovered photos of the prison's final hours. The new display opened five decades after the last shacked prisoners were taken off the infamous prison in San Francisco Bay that once held the likes of gangsters Al Capone and Mickey Cohen.