Enterprise, on one of the test flights in the late 1970s, from the Atlantic’s In Focus last year.
Why those huge wings for a glider? Maciej Cegłowski, in his classic A Rocket To Nowhere:
the Air Force demanded that the Shuttle be capable of gliding over a thousand miles cross-range during re-entry, so that it could catch up with the rapidly eastbound Air Force base underneath it. This meant bigger wings, which in turn meant more weight, an even more powerful rocket, and again a more complicated heat shield.