The Army started construction on Alcatraz Island in 1853. At that time the Army placed cannons at the north, south, and west sides of the island to provide gunfire at incoming enemy ships. On top of the island was a defensive barracks known as the Citadel. By 1861, the government designated Fort Alcatraz as the official military prison for the entire Department of the Pacific.
In 1907, the United States Department of War decided that Alcatraz Island would no longer serve as a defensive Army fort but would be used instead as a military detention barracks. Plans were drawn for a cellhouse that could accommodate up to 600 military prisoners. The construction of the building was completed in 1912.
The large building sited on the top of the island as seen in the above photo is the Alcatraz Cellhouse. The view is looking west.
The dock-level guard tower seen in this photo was constructed in 1933. This was the second of four guard towers that were built on the island. This guard tower was armed with a .30-caliber Winchester rifle with 50 rounds of ammunition, a Thompson submachine gun, a Colt .45 caliber semiautomatic pistol with three seven-round clips, three gas grenades, and two gas masks. All guards were locked inside each of the towers during their time on duty. This action was taken to ensure maximum security for each guard while occupying the guard towers.
The U.S. Government's official policy is that the three escapees died while swimming towards San Francisco; their bodies were never found. This view is looking north.
A view of a cell on the lower level of Cell Block-D.