130704-N-HN195-502 BOSTON (July 4, 2013) USS Constitution fires a 21-gun salute in honor of America's 237th birthday during the ship's annual Fourth of July turnaround cruise. More than 500 guests went underway with Old Ironsides for a three-hour tour of Boston Harbor in celebration of Independence Day. (U.S. Navy photo by Sonar Technician (Submarine) 2nd Class Thomas Rooney/Released)