I think you will find Alcatraz smack in the middle of San Francisco Bay. Named Alcatraz by a spanish explorer, it means "Home of Pelicans." Today we refer to it simply as "the Rock."
The U.S. Military built a fortress there which was later used to hold Civil War, then Spanish-American War prisoners.
It became the premiere maxium-security prison from the mid 1930's to the mid 1960's. The "worst of the worst" would be housed here. Al Capone lived here for 4 1/2 years. There is a false impression about alcatraz. The impression was that inmates served life sentences out here on "the Rock." Not true. The average sentence was 5 years. You stayed here until you proved yourself by good behavior to go on to another federal prison or got released. No execution was ever performed at Alcatraz.
There are no "man-eating" sharks in S.F. bay. Escape was hindered by strong currents and tides, along with cold water.
Robert Stroud, AKA "The Birdman of Alcatraz," never had birds here. He did move on to Leavenworth where he had, and studied birds.
Not only have I not been to Alcatraz, but no one in my family has been there!