<P> The guard change is very symbolic, but also conducted in accordance with Army regulations . The relief commander or assistant relief commander, along with the oncoming guard, are both required for a guard change to take place . The relief commander orders the guard being relieved to "pass on your orders" to the oncoming guard . The guard being relieved will say to the oncoming guard, "Post and orders remain as directed ." The oncoming guard's response is always, "Orders acknowledged ." During changes when the public is witnessing the ceremony, the commander will inform the public that the ceremony is about to take place and that those in attendance should remain "silent and standing" throughout the entire event . </P> <P> A civilian guard was first posted at the Tomb on November 17, 1925, to prevent, among other things, families from picnicking on the flat marble slab with views of the city . A military guard was first posted on March 25, 1926 . The first 24 - hour guard was posted on midnight, July 2, 1937 . The Tomb of the Unknowns has been guarded continuously, 24 hours a day, 7 days a week, since that time . Inclement weather, terrorist attacks, et cetera, do not cause the watch to cease . </P> <P> Since 1948, the Tomb Guards, a special platoon within the 3rd U.S. Infantry Regiment (The Old Guard) work on a team rotation of 24 hours on, 24 hours off, for five days, taking the following four days off . A guard takes an average of six hours to prepare his uniform--heavy wool, regardless of the time of year--for the next day's work . In addition to preparing the uniform, guards also conduct physical training, Tomb Guard training, participate in field exercises, cut their hair before the next work day, and at times are involved in regimental functions as well . Tomb Guards are required to memorize 17 pages of information about Arlington National Cemetery and the Tomb of the Unknown Soldier, including the locations of nearly 300 graves and who is buried in each one . </P> <P> A special Army decoration, the Tomb of the Unknown Soldier Guard Identification Badge is authorized for wear after passing a detailed test of 100 questions (from a pool of more than 300), a uniform test with two gigs (errors) or fewer (measured to the 1 / 64 "), and a test on the guard changing sequence . After serving honorably for a period of nine months, and having passed the sequence of tests, a Tomb Guard is permanently awarded the Badge . Since the first award on February 7, 1958, fewer than 650 soldiers have completed training and been awarded this Badge, including four women . A small number of Tomb Guard Identification Badges have also been retroactively awarded to soldiers who served as Guards before 1959 . Those numbers make the Badge the second rarest award currently issued in the United States Army; only the Army Astronaut Badge is rarer . </P>

Who is buried at the tomb of the unknowns