President Barack Obama along with first lady Michelle Obama, former president Bill Clinton, former Secretary of State Hillary Clinton lay a wreath at the grave site of John F. Kennedy, 35th U.S. president, at Arlington National Cemetery, in Arlington, Va., Nov. 20, 2013. The armed forces full honor wreath ceremony near the eternal flame marks the 50th anniversary of Kennedy's assassination. (U.S. Army photo by Gregory L. Jones)