Female Sergeant of the Guard SGT Ruth Hanks relieves the sentry of the Tomb of the Unknown Soldier at Arlington National Cemetery. The Tomb of the Unknown Soldier is guarded 24 hours a day, 365 days a year, and in any weather by Tomb Guard sentinels. Sentinels, all volunteers, are considered to be the best of the elite 3rd U.S. Infantry Regiment (The Old Guard), headquartered at Fort Myer, Va.
On March 4, 1921, the United States Congress approved the burial of an unidentified American serviceman from World War I in the plaza of the new Memorial Amphitheater. On November 11, 1921, the unknown soldier brought back from France was interred below a three-level marble tomb. The bottom two levels are six marble sections each and the top at least nine blocks with a rectangular opening in the center of each level through which the unknown remains were placed through the tomb and into the ground below. A stone other than marble covers the rectangular opening.