Alcatraz Island 1906 San Francisco earthquake, civilian prisoners were transferred to Alcatraz for safe confinement. On March 21, 1907, Alcatraz was officially designated as the Western U.S. Military Prison, later Pacific Branch, U.S. Disciplinary Barracks, 1915. In 1909 construction began on the huge concrete main cell block, designed by Major Reuben Turner, which remains the island's dominant feature. It was completed in 1912. To accommodate the new cell block, the Citadel, a three-story barracks, was demolished down to the first floor, which was actually below ground level. The building had been constructed in an excavated pit (creating a dry "moat") to enhance
June 1962 Alcatraz escape attempt to death by guards because he wouldn't help investigators locate his brothers. A 2014 study of the ocean currents by scientists at Delft University and the research institute Deltares indicates that if the prisoners left Alcatraz at 11:30 pm on June 11, they could have made it to Horseshoe Bay just north of the Golden Gate Bridge, and that any debris that were released into the bay would have floated into the direction of Angel Island, consistent with where the paddle and belongings of the prisoners' was actually found. A 2015 History Channel documentary presented further circumstantial evidence gathered over