You know the drill: guess the year this photograph was taken (and maybe what in the world could have shocked this woman so much?). We'll update later with the answer and more details.
UPDATE: Most of you were correct, this is the expression of shock a woman gave upon hearing the news of John F. Kennedy's assassination, taken in Manhattan on November 22nd, 1963. Below is video which begins showing reactions from a crowd of people near reporter Gabe Pressman's car in New York City, hearing the same news for the first time:
And another, which gets reactions from New Yorkers on the street (around the 1:20 mark):