United States Penitentiary, Alcatraz Island opened in January 1934 and closed on March 21, 1963. It housed infamous inmates such as Al Capone, George "Machine Gun" Kelly, and James "Whitey" Bulger. The penitentiary was closed because it was over 10 times more expensive to operate than other prisons, decades of exposure to salt water had severely damaged the buildings, and the bay was being polluted by sewage from the prison.