With its matching pillbox cap, and, by the end of Nov. 22, 1963, blood stains splotched across her skirt, the first lady's clothing was a colorful and tragic constant throughout the day.
The pink stands out, from the sunny moment she stepped off Air Force One, clutching a dozen red roses and standing next to a smiling President John F. Kennedy, to the somber moment on the flight back to Washington, as Vice President Lyndon Johnson became President Johnson.
"That whole scene is obviously just surreal," said Philip Shenon, author of A Cruel and Shocking Act: The Secret History of the Kennedy Assassination. "She arrives in the cabin in Air Force One in these clothes, covered with the President's blood, and she's expected to stand there and witness the swearing in of her husband's successor."
"Her remark, I think she made it more than once is, 'No, I'm going to leave these clothes on. I want them to see what they have done," Shenon said.
The first lady finally took the suit off once she returned to the White House, but it was never cleaned. An aide put the suit in a bag, and it was taken away.
The suit -- actually a knock-off Coco Chanel design made for the first lady in the United States -- was delivered to the National Archives in a box from her mother, Janet Norton Lee.
"Jackie's suit and bag -- worn November 22nd, 1963," the note said.
But despite its prominent place in history, Jackie Kennedy's suit is hidden away from view.
In 2003 Caroline Kennedy gifted it American people, on the condition it would not be displayed until 2103, and even then, only with the consultation of the Kennedy family.
The suit, along with the first lady's blue blouse, stockings, blue shoes and blue purse, are all stored in a climate-controlled room at the National Archives building in Maryland. Someday, it will likely go on display.
And while most of the mysteries surrounding that day have to do with the numerous conspiracy theories about Kennedy's assassination, there remains one about his wife: the whereabouts of her hat.
"The hat is a mystery," Shenon said. It "apparently goes to the Secret Service initially and the Secret Service turns it over to Mrs. Kennedy's private secretary, but then it disappears. It has not been seen since."