There were 4 unidentified soldiers buried in the tomb. One from WWI, WWII, Korea, and Vietnam. The Vietnam soldier was exhumed, positively identified and reburied per the family’s wishes. Reading about the selection process for which unknown soldier got the honor is wild. Particularly WWII when it came down to the final two in the selection process one got chosen for the tomb and one buried at sea after being exhumed from one resting place and traveling around the world.
I did find it interesting how important 21 is in the guarding of the tomb of the unknown soldier.