ARLINGTON, Virginia (CNN) -- Staff Sgt. Travis Nielsen had no idea when he joined the U.S. Army that his duty would include one of the most solemn and hallowed ceremonies in the military. John F. Kennedy's funeral in 1963 included a riderless horse with boots facing backwards in the saddle. During funeral processions at Virginia's Arlington National Cemetery near Washington, Nielsen walks the riderless horse, a powerful military symbol that stands among the highest honors for the fallen. Images of the so-called caparisoned horse, often referred to as the "cap horse," remain emblazoned in the memories of millions of shocked Americans who watched President Kennedy's funeral procession shortly after his 1963 assassination.
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Riderless horses honor high-ranking fallen U.S. troops, government officials
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Many recall horse with empty saddle during 1963 JFK funeral
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Army's ceremonial "Old Guard" unit prides itself on its military funerals
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Tradition of riderless horses at funerals dates to ancient Rome, soldier says
"We carry @placeholder's heroes to the final resting place," he said.