The Arlington National Cemetery is the final resting place of the brave souls who gave their lives in service to the country. Two of America's former presidents, John F. Kennedy and William Howard Taft are buried here. The crew of the Challenger space shuttle, civil rights leader Medgar Evers and film star Audie Murphy are among the many honored here. The Tomb of the Unknown Soldiers, containing remains of unidentified soldiers from World Wars I, II, and the Korean War, are protected by the 3rd U.S. Infantry Regiment or the Old Guard 24 hours a day. The changing of the guard ceremony is a moving tribute to them.