Power House, Power station on Alcatraz Island, San Francisco, US

Power House is a multi-storey concrete building on the northwest coast of Alcatraz Island, its pale weathered facade pierced by columns of rectangular windows and topped by a gabled roof with a small louvered vent. A tall cylindrical smokestack with a side ladder rises at its rear left. Built in 1939, it held the generators that powered the federal penitentiary and other island buildings until 1963.

The Power House was completed in 1939 at a cost of $186,000, part of a $1.1 million modernization that also added the water tower, the New Industries Building, officers' quarters and a remodel of D-block. It supplied electricity to the federal penitentiary and other island buildings until 1963. Its white smokestack and the lighthouse were said to give the appearance of a ship's mast on either side of the island.

The white smokestack and the lighthouse were said to give the island the look of a ship's masts on either side. A sign in front read "Warning. Keep Off. Only Government permitted within 200 yards" to keep boats from landing at this point.

The Power House stands on the northwest coast of Alcatraz Island, where a sign once warned "Keep Off. Only Government permitted within 200 yards" to stop boats landing at that point. The building is seen from outside; the interior is not open to visitors. Look for the white smokestack and the lighthouse, which together were said to resemble a ship's masts on either side of the island.

The Power House tower contained specific security equipment: a Winchester rifle, a Colt pistol, gas grenades, and a gas mask for guard protection.