Members of the 3rd U.S. Infantry Regiment - “The Old Guard” - have guarded the Tomb of the Unknown Soldier every second, of every day regardless of weather or holidays since April 6, 1948.
“The Old Guard” is the Army's official ceremonial unit and escort to the president, and it also provides security for Washington, D.C., in time of national emergency or civil disturbance.
The unit received its unique name from Gen. Winfield Scott during a victory parade at Mexico City in 1847 following its valorous performance in the Mexican War. Fifty campaign streamers attest to the 3rd Infantry's long history of service, which spans from the Battle of Fallen Timbers to World War II and Vietnam.
Since World War II, “The Old Guard” has served as the official Army Honor Guard and escort to the President. In that capacity, 3rd Infantry soldiers are responsible for conducting military ceremonies at the White House, the Pentagon, national memorials and elsewhere in the nation's capital. In addition to their 24-hour vigil at the Tomb of the Unknown Soldier, soldiers of “The Old Guard” provide military funeral escorts at Arlington National Cemetery and participate in parades at Fort Myer and Fort Lesley J. McNair.
For more on “The Old Guard” go to http://www.army.mil/info/organization/unitsandcommands/commandstructure/theoldguard/