The sentinel marches 21 steps across the black mat, past the final resting places of the Unknown Soldiers of World War I, World War II, Korea, and the empty crypt of the Unknown Soldier of the Vietnam War. With a crisp turn, the sentinel turns 90 degrees to face east for 21 seconds. The sentinel then turns a sharp 90 degrees again to face north for 21 seconds. A crisp 'shoulder-arms' movement places the rifle on the shoulder nearest the visitors to signify that the sentinel stands between the tomb and any threat. After the moment, the sentinel paces 21 steps north, turns and repeats the process. The practiced cadence is timed so that the sentinel paces at a rate of 90 steps each minute.

The sentinel marches 21 steps across the black mat, past the final resting places of the Unknown Soldiers of World War I, World War II, Korea, and the empty crypt of the Unknown Soldier of the Vietnam War. With a crisp turn, the sentinel turns 90 degrees to face east for 21 seconds. The sentinel then turns a sharp 90 degrees again to face north for 21 seconds. A crisp 'shoulder-arms' movement places the rifle on the shoulder nearest the visitors to signify that the sentinel stands between the tomb and any threat. After the moment, the sentinel paces 21 steps north, turns and repeats the process. The practiced cadence is timed so that the sentinel paces at a rate of 90 steps each minute.