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.
Escape from Alcatraz (triathlon) foot race, but by making it an out-and-back run rather than a one-way course, became known as a "Double Dipsea". The course has remained the same over the years and celebrated its 35th anniversary in 2015. Participants are limited to members of the Dolphin Club and The South End Club. The Dolphin Club is the host and sponsor of the event. The annual public Escape from Alcatraz triathlon, organized by IMG, now takes place in early June. The current course consists of a swim starting near Alcatraz Island, a run from the bay to the transition zone at Marina Green,