Eve Arnold, Ladies' Room, the old Metropolitan Opera House in New York.
Wonderful photo of a Charles James' La Sirène evening dress- for me, as a fashion historian, there is nothing better than a photograph of the original wearer in a dress (except a video of them moving in it). James' gowns are technically so wondrous that it can be sometimes hard to imagine them ever existing in another realm that the museum platform. The intimacy of this photo shows the pulls and the gapes, the qualities a dress takes on only when it becomes one with a human body.