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
Recreation Yard (Alcatraz) Recreation Yard (Alcatraz) The Recreation Yard was the yard used by inmates of Alcatraz Federal Penitentiary between 1934 and 1963. It is located opposite the Dining Hall south of the end of D-Block on a raised level surrounded by a high wall and fence above it. Guard Tower #3 lay just to the west of the yard. The gun gallery was situated in the yard, mounted on one of the dining hall's exterior walls. The recreation yard faced the mainland. In 1936, the previously dirt-covered yard was paved. The yard was part of the most violent escape attempt from Alcatraz