The USS Constitution fires a 21-gun salute. The USS Constitution fires a 21-gun salute to Castle Island's Fort Independence during its annual turn-around cruise in Boston Harbor, Mass., on June 10, 2006. USS Constitution, known as Old Ironsides, is the oldest commissioned ship in the world afloat. SHARE IMAGE: Download Image: Full Size (0.03 MB) Photo By: VIRIN: 930145-W-RSG48-305.jpg Photo Gallery