Unknown Soldier, Tomb of the, form of memorial to a nation's war dead, adopted by many countries after World War I. The Tomb of the Unknowns, a memorial to the American dead of World Wars I and II, the Korean War, and the Vietnam War, is in Arlington National Cemetery, just outside Washington, D.C. On Nov. 11, 1921, an unidentified soldier who had been killed in France was buried there in a temporary crypt over which a marble slab was placed; the completed tomb, a sarcophagus of Colorado marble placed on the original base, was dedicated as the Tomb of the Unknown Soldier on Nov. 11, 1932. On Memorial Day, 1958, the bodies of two other unknown soldiers—one of whom had died in World War II, the other during the Korean War—were buried in the tomb, which was renamed the Tomb of the Unknowns. Remains of an unknown soldier from the Vietnam War were interred here in 1984, but later investigations revealed the soldier's identity, and they were removed. Deciding that scientific advances, including DNA tests (see DNA fingerprinting), had made Vietnam War or future unknowns unlikely, the Pentagon announced (1999) that no new remains would be placed in the memorial.

The best known of other such memorials are those in Westminster Abbey in London and under the Arc de Triomphe in Paris. Similar tombs are in Baghdad, Russia, and elsewhere.

Nickname given to members of African American cavalry regiments of the U.S. Army who served in the western U.S. (1867–96). An 1866 law authorized the army to form cavalry and infantry regiments of African American men under the command of white officers; the result was the 9th and 10th cavalries and the 38th through 41st infantries. The primary mission of the cavalry regiments was to control Indians on the western frontier (the nickname “buffalo” was given by the Indians). The soldiers took part in almost 200 engagements. Noted for their courage and discipline, they had the army's lowest desertion and court-martial rates. One of the 10th Cavalry's officers was John Pershing, whose nickname “Black Jack” reflected his advocacy on behalf of African American troops.

Learn more about buffalo soldier with a free trial on Britannica.com.