180518-N-AE894-0241 BOSTON (May 18, 2018) The USS Constitution fires a 21-gun salute to Fort Independence on Castle Island during the ship's underway commemorating the Vietnam War. In coordination with the United States of America Vietnam War Commemoration, the crew of USS Constitution hosted Vietnam veterans as a thank you for their years of service and sacrifice for their country. (U.S. Navy photo by Seaman Donovan Keller/Released)