Okay, here is the story:
A B-17 from the 414th squadron of the 97th bomb group has a mid-air collision with a German fighter (Don't remember off the top of my head, but I think it was a FW-190, please correct me if that is not the case). The German fighter goes down. Miraculously, the B-17 still flies, making it home. After landing and the crew got out, the back finally broke in 2. The picture tells the story though. Testament to the Forts durability, and the crew's luck. Brave guys to stay with it when it was that bad!
Photos courtesy of the USAF Museum collection website.