Alcatraz Island was originally explored as a seabird habitat in 1775 by Lieutenant Juan Manuel de Ayala. He named it Isla de los Alcatraces meaning Isle of the Pelicans. During the Civil War, 1861-1865, a prisoner of war camp was erected on the island. Serving as a federal prison from 1934 to 1963, Alcatraz held some of the United States’ most notorious criminals, such as Al Capone, George “Machine Gun” Kelly and Robert Stroud, also known as the “Birdman of Alcatraz”. Upon its closure, it became and remains a popular tourist destination.