Tomb of the Unknown Soldier is overlooking Washington D.C, and is at the Arlington Cemetery. Congress approved to bury the unknown soldier on March 4, 1921. The tombstone is white marble and is flat faced. The stone also has three Greek words that say peace, victory, and valor. The tomb represent all of the other soldiers who were unknown in World War I, Korea, and Vietnam.
Also, when you are there you can visit other graves of presidents, and see the changing of the guard. At the cemetery you can see George Washington, JFK and his family, Lincolns family, and William Howard Taft.