Alcatraz Federal Penitentiary and the island became a prison of the Federal Bureau of Prisons in August 1934 after the buildings were modernized to meet the requirements of a top-notch security prison. Given this high security and the location of Alcatraz in the cold waters and strong currents of San Francisco Bay, the prison operators believed Alcatraz to be escape-proof and America's strongest prison. Alcatraz was designed to hold prisoners who continuously caused trouble at other federal prisons. One of the world's most notorious and best known prisons over the years, Alcatraz housed some 1,576 of America's most ruthless criminals including Al Capone,
Alcatraz Federal Penitentiary Alcatraz Federal Penitentiary The Alcatraz Federal Penitentiary or United States Penitentiary, Alcatraz Island (often just referred to as Alcatraz or The Rock) was a maximum high-security federal prison on Alcatraz Island, off the coast of San Francisco, California, which operated from August 11, 1934, until March 21, 1963. The main prison building was built in 1910–1912 during its time as a United States Army military prison; Alcatraz had been the site of a citadel since the 1860s. The United States Disciplinary Barracks, Pacific Branch on Alcatraz had been acquired by the United States Department of Justice on October 12, 1933,