The Gubeikou section of the Great Wall is a little over two hours outside Beijing. It connects to the Jinshanling section if you are looking for a serious wild wall walk. Unlike Jinshanling, Mutianyu and Badaling, where the Great Wall has been restored to a picture perfect and safe state, Gubeikou is in its original condition. It is crumbling, much of it has no safety ledges and it has a lot of loose rock. If you are accustomed to hiking in wild areas, then you will enjoy Gubeikou. You can walk to Jinshanling passing through many watchtowers and going up and down many hills on the way. There is a military base along the way between Gubeikou and Jinshanling, so be prepared for a detour away from the wall to get around the military base.