FACTS ABOUT THE TOMB OF THE UNKNOWN SOLDIER

1. On Nov. 11, 1921, President Harding dedicated the Tomb of the Unknown Soldier. The sarcophagus was designed by architect Lorimer Rich and sculptor Thomas Hudson Jones. It was actually carved by the Piccirilli Brothers.  They had earlier done the statue of Lincoln in the Lincoln Memorial.  The three carved Greek figures represent peace, victory, and valor.
2. The WWI representative was chosen from four bodies exhumed from four separate cemeteries in France. Sgt. Edward F. Younger (Distinguished Service Medal awardee) chose from the four caskets by placing some white roses on it.  The casket was brought to the U.S. on the USS Olympia.
3. After WWII, Medal of Honor recipient Hospitalman 1^st Class William R. Charette chose from one body from the Pacific and one from Europe.
4. The Vietnam War representative was tabbed in 1984 by Marine Sgt. Maj. Allan Jay Kellogg, Jr. The Medal of Honor hero chose the casket in 1984.  However, in 1988 the casket was opened up for DNA testing and revealed to be Air Force 1^st Lt. Michael Joseph Blassie.  He was reburied by his family in St. Louis.  Since there were no other unidentified corpses from Vietnam, there is no representative from that war.  Because of advanced scientific methods, the military has had no unidentified personnel since Vietnam.
5. The guards are volunteers from the 3^rd Infantry Regiment, the “Old Guard”. This is the oldest active duty unit in the Army, having been created in 1784.  You have to pass a rigorous test and go through intense training.  Guards must memorize al  35 pages of the history of the tomb.  They are under a strict moral code which still applies after their service is over.  Guards get the Tomb Guard Badge which is the rarest in the Army and second only to the astronaut badge in the whole military.  Only three women have earned the badge.
6. Constant guarding began in 1937. Guards work 24 hour shifts and “walk the mat” for ½ hour from April 1-September 30.  The shifts are one hour from October 1-March 31.  When you are not on duty, you spend your time in the living quarters below the tomb.  It takes up to eight hours to prepare the uniform which has the highest standards in all the military.
7. The guard marches 21 steps (in honor of the 21-gun salute), stops, faces the tomb for exactly 21 seconds, and then repeats the process.

https://www.mentalfloss.com/article/71005/10-facts-about-tomb-unknown-soldier

https://www.cnn.com/2019/05/27/us/tomb-of-the-unknown-soldier-trnd/index.html

https://www.wearethemighty.com/military-life/facts-tomb-unknown-soldier/