Alcatraz Island, a small rocky island in San Francisco Bay, evolved from a mid-19th-century military reservation and fortified coastal defense post into a place of confinement whose isolation in cold, swift water made it especially secure. The Army used it to hold military offenders, prisoners of war, Confederate sympathizers, and other detainees before it shifted fully toward imprisonment, with a major cell block completed in 1912. Transferred to the Department of Justice, it reopened in 1934 as a federal penitentiary that held notorious inmates under strict security. After closing in 1963, it became a major site of Native American protest, later a protected historic place, and a leading San Francisco destination.

Photo: Wikipedia · Public domain

Photo: Wikipedia · Public domain

Photo: Wikipedia · Public domain

San Francisco, California · USA