The Tomb of the Unknown in Arlington Cemetery is a very sacred place for all Americans. It is a monument dedicated to American service members who have died without their remains being identified.  A single soldier guards the tomb at any given time.  This soldier is known as a "Tomb Guard" and this honor is the second least-awarded decoration in the United States Military.

The Tomb Guards request an atmosphere of silence and respect for the Tomb of the Unknowns.  The guard will confront you if you are being disrespectful or are in an area you should not be.

The tomb guard follows a strict routine when guarding the tomb:

  1. Marches 21 steps south down the black mat laid across the Tomb.
  2. Turns and faces east, toward the Tomb, for 21 seconds.
  3. Turns and faces north, changes weapon to outside shoulder, and waits 21 seconds.
  4. Marches 21 steps down the mat.
  5. Turns and faces east for 21 seconds.
  6. Turns and faces south, changes weapon to outside shoulder, and waits 21 seconds.
  7. Repeats the routine until the soldier is relieved of duty at the Changing of the Guard.

[Source: Wikipedia]