On the plane back to Washington, in her pink Chanel suit, caked with her husband’s blood, Jackie Kennedy resisted all suggestions from aides that she clean herself up. Instead, she just said, “Let them see what they’ve done.”

But for the half century since John F. Kennedy’s assassination in Dallas on Nov. 22, 1963, the most famous artifact from that day, one of the most recognizable articles of clothing ever worn, has been seen by almost no one. Now preserved by the National Archives in a climate-controlled vault outside of Washington, it is subject to Kennedy family restrictions that it not be seen for almost a century more.