The Tomb of the Unknown Soldier honors the unknown servicemen who have fallen in the four major U.S. Conflicts of the 20th Century: World War I, World War II, the Korean Conflict, and the Vietnam Conflict. In 1926, the tomb was placed under a day guard during the hours which the cemetery was open to visitors, but in 1937, the tomb was placed under a 24-hour military honor guard. The responsibility of the guarding of the tomb was taken over by the Third United States Infantry, "The Old Guard" in 1948, and the practice continues today. To be a tomb...