The commander of U.S. Transportation Command honored U.S. merchant mariners, past and present, May 19 during Military Sealift Command's (MSC) annual National Maritime Day memorial service and wreath-laying ceremony at the historic Washington Navy Yard in Washington, D.C. National Maritime Day, officially May 22, was established by Congress in 1933 and is observed each year to honor the contributions and sacrifices of U.S. merchant mariners in defense of the nation. These dedicated men and women are frequently considered the unsung heroes of the nation's defense. MSC is the largest employer of U.S. merchant mariners with more than 7,000 civil service and contract mariners deployed worldwide providing critical support to U.S. and allied warfighters around the world.