1.5 miles offshore from San Francisco lies Alcatraz island. The island was initially developed as a military garrison and then in 1868 it became a military prison. In 1934, Alcatraz became a federal prison housing some of America's worst criminals.
The penitentiary was only in operation for 29 years. It claimed that no prisoner successfully escaped. A total of 36 prisoners made 14 escape attempts, two men trying twice; 23 were caught, six were shot and killed during their escape, two drowned, and five are listed as "missing and presumed drowned".