The eternal flame shines in the early morning light at the grave of John F. Kennedy at Arlington National Cemetery on Friday, Nov. 22, 2013, on the 50th anniversary of Kennedy's death. (AP Photo/Jacquelyn Martin)
The caisson bearing the flag-draped coffin of Kennedy leaves the White House in procession down Pennsylvania Avenue en route to Arlington National Cemetery.
FILE - In this Tuesday, Oct. 29, 2013 file photo, Arlington House sits atop a hill overlooking the eternal flame at the grave site of President John F. Kennedy at Arlington National Cemetery in Arlington, Va. (AP Photo/Susan Walsh, File)
FILE - In this Nov. 25, 1963 file photo, an Irish cadet honor guard, center rows holding rifles, stands in formation as the U.S. flag is lifted from the coffin of President John F. Kennedy during his funeral services at Arlington National Cemetery in Arlington, Va. (AP Photo)
FILE - In this Monday, Nov. 25, 1963 file photo, Jacqueline Kennedy, widow of assassinated President John F. Kennedy, holds the U.S. flag that covered the coffin of her husband at Arlington National Cemetery in Arlington, Va. after he was buried. (AP Photo/Eddie Adams)