The Boston Navy Yard was one of the oldest shipbuilding places in the United States Navy. It was first called the Charlestown Navy Yard and later Boston Naval Shipyard. It was started in 1801. It was officially closed as an active naval yard on July 1, 1974. It still has the ship the USS "Constitution" docked there. The USS "Cassin Young", a World War II-era destroyer, is there and is a museum ship.