The great wall of China is composed of several sections that are today not well maintained. The old towers are now more looking like ruins than fortifications. Yet, the shadow of the wall still guard the northern mountains for now centuries. Most of foreigners wishing to visit the wall will usually choose Badaling (which is actually the less interesting part as usually crowded and not very authentic) or Jinshanling (much more beautiful and fascinating). However, most of locals or agencies will know other hidden but accessible sections which will probably give you even more memorable experiences.
Once you finally access to the wall (most of the time, in a clean section officially opened to visitors and renovated), you can keep walking in one direction. After some time, you will probably find a sign in chinese and english informing you that you are now facing a section close to public. You will probably make a mistake to not cross this limit. In fact, after keeping walking in the same directions for some time, you will reach the most interesting parts of the wall. These very authentic sections have never been renovated, and didn’t really change since they were build. Walking there can be however difficult and even dangerous. But what a feeling and experience! The picture above says all!