Below is President Reagan's 1984 speech at the Tomb of the Unknowns, one of his finest (a week later, he'd top it at Point Du Hoc, honoring the 40th anniversary of Operation Overlord in a beautiful, soaring address). The tomb, which contains the remains of soldiers -- or known only to God, as the inscription goes -- from World War I, World War II and Korea. Remains from each conflict were chosen at random from a larger selection of caskets, traditionally by a combat decorated serviceman.
Reagan made a heartfelt plea to the American people and the government of Hanoi to return the remains of U.S. servicemen home for proper burial. Though inconceivable at the time of dedication, especially considering that DNA testing developed afterward, the grave of the Vietnam unknown was exhumed for testing in 1998, identifying the remains as those of Lt. Michael Blassie, an A-37 Dragonfly pilot who was shot down over An Loc in southern Vietnam. He was later reburied by his family in Missouri.
Thanks to advances in mitochondrial DNA testing, it's likely that the remains of the World I and World War II-Korea unknowns will be the last to grace the hallowed tomb. But, worthy of remembrance, tens of thousands of fallen U.S. servicemen are still classified as missing in action.