Alcatraz started its existence as a military fort. During the Civil War it was used to house Confederate prisoners. In 1934 it was transferred to the Federal Bureau of Prisons where it served as a prison until 1963.
An overall shot of the island.
A closeup using my monster lens.
Another closeup showing the lighthouse and the prison.
I didn't get a chance to go out to the island but I hear that it is pretty neat.