As befits the world's only superpower the United States has lots of unknown soldiers and some have even become known.
The picture above shows the Tomb of the Unknowns. The World War I unknown is below the marble sarcophagus. The other unknowns are beneath the white slabs on the ground. From left to right they are the World War II unknown, the Vietnam unknown, and the Korean War unknown.
The remains of the Vietnam Unknown were exhumed May 14, 1998 and based on mitochondrial DNA testing, the remains have been identified and returned to the family.
The original inscription of 'Vietnam' and the dates of the war has been changed to 'Honoring and Keeping Faith with America's Missing Servicemen'.