http://www.arlingtoncemetery.mil/ http://www.arlingtoncemetery.mil/Explore-the-Cemetery/Tomb-of-the-Unknown-Soldier The Tomb of the Unknown Soldier Tomb of the Unknown Soldier at Arlington National Cemetery The Tomb of the Unknown Soldier at Arlington National Cemetery stands atop a hill overlooking Washington, D.C. On March 4, 1921, Congress approved the burial of an unidentified American soldier from World War I in the plaza of the new Memorial Amphitheater. The white marble sarcophagus has a flat-faced form and is relieved at the corners and along the sides by neo-classic pilasters, or columns, set into the surface. Sculpted into the east panel which faces Washington, D.C., are three Greek figures representing Peace, Victory, and Valor. The six wreaths, three sculpted on each side, represent the six major campaigns of World War I. Inscribed on the back of the Tomb are the words: Here rests in honored glory an American soldier known but to God The Tomb sarcophagus was placed above the grave of the Unknown Soldier of World War I. West of the World War I Unknown are the crypts of unknowns from World War II, Korea and Vietnam. Those three graves are marked with white marble slabs flush with the plaza. http://www.arlingtoncemetery.mil/Explore-the-Cemetery/Changing-of-the-Guard The Changing of the Guard Changing of the Guard Ritual The guard is changed every hour on the hour October 1 to March 31 in an elaborate ritual. From April 1 through September 30, there are more than double the opportunities to view the change because another change is added on the half hour and the cemetery closing time moves from 5:00 to 7:00 p.m. An impeccably uniformed relief commander appears on the plaza to announce the Changing of the Guard. Soon the new sentinel leaves the Quarters and unlocks the bolt of his or her M-14 rifle to signal to the relief commander to start the ceremony. The relief commander walks out to the Tomb and salutes, then faces the spectators and asks them to stand and stay silent during the ceremony. The relief commander conducts a detailed white-glove inspection of the weapon, checking each part of the rifle once. Then, the relief commander and the relieving sentinel meet the retiring sentinel at the center of the matted path in front of the Tomb. All three salute the Unknown who have been symbolically given the Medal of Honor. Then the relief commander orders the relieved sentinel, "Pass on your orders." The current sentinel commands, "Post and orders, remain as directed." The newly posted sentinel replies, "Orders acknowledged," and steps into position on the black mat. When the relief commander passes by, the new sentinel begins walking at a cadence of 90 steps per minute. The Tomb Guard marches 21 steps down the black mat behind the Tomb, turns, faces east for 21 seconds, turns and faces north for 21 seconds, then takes 21 steps down the mat and repeats the process. After the turn, the sentinel executes a sharp "shoulder-arms" movement to place the weapon on the shoulder closest to the visitors to signify that the sentinel stands between the Tomb and any possible threat. Twenty-one was chosen because it symbolizes the highest military honor that can be bestowed -- the 21-gun salute.