Once little more than a potter's field, Arlington Cemetery has become a national shrine and a treasury of American history.

Once little more than a potter's field, Arlington Cemetery has become a national shrine and a treasury of American history. Both the famous and the obscure are buried here, from John F. Kennedy and the Unknown Soldiers to astronauts from the space shuttle Challenger, polar explorers Peary and Henson, and some 3,000 freed slaves. On the 140th anniversary of the first burial at Arlington in May 1864, National Geographic presents a portrait of one of America's most sacred places. Viewers take a privileged behind-the-scenes look at the intense daily rituals and activities of a military cemetery, through rare archival footage and the real-life stories of the heroes and heroines buried here. They also meet the people who make the cemetery work, defining it with their service.