Alcatraz Island the hands of Confederate sympathizers. Alcatraz, built as a "heavily fortified military site on the West Coast", formed a "triangle of defense" along with Fort Point and Lime Point, and ensured security to the bay. The island was also the site of the first operational lighthouse on the West Coast of the United States. Alcatraz never fired its guns offensively, though during the war it was used to imprison Confederate sympathizers and privateers on the west coast. Because of its isolation from the outside by the cold, strong, hazardous currents of the waters of San Francisco Bay, Alcatraz was used
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,