San Francisco Bay is the artificial and flat Treasure Island, site of the 1939 Golden Gate International Exposition. From the Second World War until the 1990s, both islands served as military bases and are now being redeveloped. Isolated in the center of the Bay is Alcatraz, the site of the famous federal penitentiary. The federal prison on Alcatraz Island no longer functions, but the complex is a popular tourist site. Despite its name, Mare Island in the northern part of the bay is a peninsula rather than an island. San Francisco Bay is thought to represent a down-warping of the Earth's crust between
Alcatraz Federal Penitentiary legendary prison" suited to the times, which resulted in the Alcatraz Island Federal Penitentiary being nicknamed "Uncle Sam's Devil's Island." Despite Alcatraz being designed to house the "worst of the worst" of criminals who caused problems at other prisons, under the guidelines and regulations set by the strict prison administrators, courts could not direct a prisoner to be directly sent to Alcatraz, however notorious they were for misbehavior and attempted escape from other prisons. Prisoners entering Alcatraz would undergo vigorous research and assessments prior to their arrival. Security in the prison was very tight, with the constant checking of bars,