The USS Constitution fires a 21-gun salute toward Fort Independence on Castle Island during the ship's annual under way in Boston Harbor on July 4, 2011. The Boston Harborfest is a six-day festival showcasing Boston's Colonial and maritime heritage. First launched in 1797, Constitution, also known as "Old Ironsides," was one of six ships ordered for construction by President George Washington to protect America's growing maritime interests and is the oldest commissioned warship afloat in the world.