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 Citadel Grounds were located in the left centre. When the new concrete prison was built in 1910-2, iron staircases in the interior were retained from the old citadel and massive granite blocks originally used as gun mounts were reused as the wharf's bulkheads and retaining walls. Alcatraz Citadel Alcatraz Citadel, also known as Fort Alcatraz, was the original military defense and prison on Alcatraz Island, off the coast of San Francisco, California, United States. The citadel was built in 1859 as a U.S. Army military defense, and began function as a war camp in 1861 and long-term military prison in 1868.