In 1921, an unknown World War I American soldier was buried in Arlington National Cemetery on a hillside overlooking the Potomac River and the city of Washington D.C. It soon became the focal point of reverence for America's veterans.

The focal point for official, national ceremonies for Veterans Day continues to be the memorial amphitheater built around the Tomb of the Unknowns. At 11 a.m. on November 11, a combined color guard representing all military services executes "Present Arms" at the tomb. The nation's tribute to its war dead is symbolized by the laying of a presidential wreath. The bugler plays "taps." The rest of the ceremony takes place in the amphitheater.

Tomb of the Unknown Soldier.......This must take a special kind of person. 
  
1. How many steps does the guard take during his walk across the tomb of  the Unknowns and why?
   21 steps. It alludes to the twenty-one gun salute, which is the highest
   honor given any military or foreign dignitary.
  
2. How long does he hesitate after his about face to begin his return walk
   and why?
   21 seconds for the same reason as answer number 1.
  
3. Why are his gloves wet?
   His gloves are moistened to prevent his losing his grip on the rifle.
  
4. Does he carry his rifle on the same shoulder all the time, and if not,
   why not?
   He carries the rifle on the shoulder away from the tomb. After  his march
   across the path, he executes an about face, and moves the rifle to the
   outside shoulder.
  
5. How often are the guards changed?
   Guards are changed every thirty minutes, twenty-four hours a day, 365 days a year.
  
6. What are the physical traits of the guard limited to?
   For a  person to  apply for guard duty at the tomb, he must be between 5'
   10" and 6' 2" tall and his waist size cannot exceed 30."
   Other requirements of the Guard:
   They must commit 2 years of life to guard the tomb, live in a  barracks
   under the tomb, and cannot drink any alcohol on or off duty for the rest of
   their lives. They cannot swear in public for the rest of their lives and
   cannot disgrace the uniform {fighting} or the tomb in any way.  After two
   years, the guard is given a wreath pin that is worn on their lapel
   signifying they served as guard of the tomb. There are only 400 presently
   worn.
  
The guard must obey these rules for the rest of their lives or give up the
  wreath pin.
  
The shoes are specially made with very thick soles to keep the heat  and
   cold from their feet. There are metal heel plates that extend to the  top
   of  the  shoe in order to make the loud click as they come to a halt. There
   are  no  wrinkles, folds or lint on the uniform.
  
Guards dress for duty in front of a full-length mirror.
  
The first six months of duty a guard cannot talk to anyone, nor watch TV.
   All off duty time is spent studying the 175 notable people laid to rest in
   Arlington National Cemetery. A guard must memorize who they are and where
   they are interred.  Among the notables are: President Taft, Joe E. Lewis
   {the  boxer} and Medal of Honor winner Audie Murphy, {the most decorated
   soldier of WWII} of Hollywood fame.
  
Every guard spends five hours a day getting his uniforms ready for guard
   duty.
  
ETERNAL REST GRANT THEM O LORD, AND LET PERPETUAL LIGHT  SHINE UPON THEM.
  
I don't know if you saw this in the news but it really impressed me.  Funny, our US Senate/House took 2 days off as they couldn't work because of the expected storm. On the ABC evening news, it was reported tonight that, because of the dangers from Hurricane Isabelle approaching Washington DC, the military members assigned the duty of guarding the Tomb of the Unknown Soldier were  given permission to suspend the assignment. They respectfully declined the offer, "No way, Sir!"  Soaked to the skin, marching in the pelting rain of a tropical storm, they said that guarding the Tomb was not just an assignment, it was the highest honor that can be afforded to a serviceperson.  The tomb has been patrolled continuously, 24/7, since 1930.