On every hour in the winter while Arlington is open, and on every half-hour in the summer (April 1 through Sept. The cover has been replaced with one with this inscription: The Army made the decision to leave the Vietnam crypt empty. He was reinterred at Jefferson Barracks National Cemetery on the banks of the Mississippi in St. Blassie's remains were returned to his family. Louis, Missouri, a pilot shot down over Vietnam in 1972. In 1998, after investigations pointed to the identity of the Vietnam unknown, the remains were exhumed and later positively identified, through DNA testing, as those of 1st Lt. The ceremonial unknowns of WWII and Korea were interred at the Tomb of the Unknown Soldier in 1958, and the Vietnam War unknown was ceremoniously interred on Memorial Day in 1984. Some are just right next to the tomb plaza.'

'We recently placed a flag on every gravesite for Memorial Day during 'Flags-In.' I've seen hundreds of unknown markers myself.

If known, there will be a date of demise,' Von Jett says of the other unknowns at Arlington. 'Generally, their gravestones read 'Unknown' and then what service the unknown served with, if known. The soldiers in the Tomb of the Unknown Soldier are among more than 5,000 unidentified soldiers buried throughout the 624 acres of Arlington National Cemetery. These honor the unknown dead of World War II, Korea and Vietnam.

Over the years, to the west of the original tomb, three other graves were erected, marked with white marble slabs that are flush to the ground.

Tomb of the unknown