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 Prisons. The purpose of this transfer was to punish those involved in the rampant crime which prevailed in the country in the 1920s and 1930s. The United States Disciplinary Barracks on Alcatraz was acquired by the United States Department of Justice on October 12, 1933, and the island became a Federal Bureau of Prisons federal prison in August 1934. The $260,000 conversion to the federal prison took place from January 1934. George Hess of the United States Public Health Service was appointed the chief medical officer of the prison and Edward W. Twitchell became a consultant in psychiatry for Alcatraz