Chris Sharma and Stefan Glowacz, two climbing legends and mutual admirers, have teamed up for something big, but they're not saying what it is. Red Bull gives three clues: "The route is big, unique, and has never been done before and likely will never be done again." Our top three guesses are 1. Huge cave in Oman, 2. The Dawn Wall (take that Caldwell), 3. Big wall on the moon (hard moves, difficult approach, low gravity).What do you think they're climbing? Tell us in the comments.