SAN FRANCISCO, CA - MARCH 21:  National Park Service ranger Roger Goldberg walks through the main cell block at Alcatraz Island on March 21, 2013 in San Francisco, California.  The National Park Service marked the 50th anniversary of the closure of the notorius Alcatraz federal penitentiary with an exhibit of newly discovered photos by Los Angeles freelance photographer Leigh Wiener of the prison's final day in 1963. Alcatraz was first a fort and later became an Army disciplinary barracks before being taken over by the Bureau of Prisons in 1934.  (Photo by Justin Sullivan/Getty Images)
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