Great Wall, whichever part you wanted to visit he is the man to go to. We chose to take the cable car up and down and walk the Wall from Mutianyu to Jiankou - it was unbelievable, words just can't express how amazing the whole experience was. The views, the feel of the history in every step and stone. We didn't want to leave, it was so magnificent. We would highly recommend Jonny for whatever part of the wall you want to visit, the difficult for the very fit, or the more gentle parts for the not so fit. He does overnight camping on the wall, whatever you choose to do you will enjoy.