On this day, 93 years ago, the Tomb of the Unknown Soldier was dedicated at Arlington National Cemetery. The event purposefully coincided with the national commemoration of Armistice Day (the end of World War I).
The unidentified remains of a soldier killed in World War I were laid to their final rest in a ceremony presided over by President Warren G. Harding - exactly three years to the day after the end of the Great War. The soldier had fallen somewhere on the battlefields of France and in remembrance of this fact, a two inch layer of French soil was placed beneath his coffin so that he might eternally rest upon the ground where he died. Arlington National Cemetery's website relates the story of how his remains were chosen,
...four unknowns were exhumed from four World War I American cemeteries in France. U.S. Army Sgt. Edward F. Younger, who was wounded in combat, highly decorated for valor and received the Distinguished Service Medal in "The Great War, the war to end all wars," selected the Unknown Soldier of World War I from four identical caskets at the city hall in Chalons-sur-Marne, France, Oct. 24, 1921. Sgt. Younger selected the unknown by placing a spray of white roses on one of the caskets. He chose the third casket from the left. The chosen unknown soldier was transported to the United States aboard the USS Olympia. Those remaining were interred in the Meuse Argonne Cemetery, France.
The national observance of Armistice Day was refocused towards honoring our nation's former servicemen and women with the creation of Veterans Day in 1954. By 1956, it was decided that the scope of the memorial should be expanded to include unknown remains from WWII and Korea. During the Reagan administration, the remains of an unknown Vietnam soldier were added - only to be later disinterred after the soldier was successfully identified.
The tomb itself didn't take it's final shape until 1932, when the carving of the great marble superstructure was completed. Today, the Tomb exists as one of our nation's most sacred shrines and the Changing of the Guard ceremony at the Tomb is a must see for visitors to Washington, DC.