Alcatraz Island Lighthouse island (they collected eggs from the large flock of birds that regularly gathered there), Alcatraz got its name in 1775 only when Juan de Ayala, a Spaniard was engaged to survey the harbor and the San Francisco Bay. Since he observed pelicans in large numbers on the island he named the island as "Isla de los Alcatraces" meaning the "Island of Pelicans". The island is separated from the main land by more than . The gold rush and the inherent risk of the choppy waters of the west coast prompted the urgent need for establishing lighthouses. Congress recognized the need
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