Is it possible that there is no such thing as a horn that will bring down the wall? Or maybe some like "It was lost to time". I was thinking that in keeping with the idea that prophecies always come true, whether explicitly or some round about way, it would still be true (there was a horn at one point, but now its gone). I don't want to see the wall come down becuase why bother having a horn to destroy the wall if your not gonne use it. Its just a mcguffin.