A far less bustling section of The Great Wall, Mutianyu (慕田峪长城) offers travelers an opportunity to experience the more raw and traditional structure of The Great Wall. Mutianyu is about a two hour drive outside of Beijing, but well worth the trip. The terrain is a little more mountainous, the structures are generally not restored, and crowds are relatively small compared to other sections of the Wall.
Depending on the time of year, it's best to leave early in the day and be able to explore the paths of Mutianyu during mid day when the sun is at its peak (though that could be painful during the hottest parts of summer). However, basking in the glow of the sun while it lights up the lush hills of Chinese countryside, knowing that you are standing on a structure that has literally thousands of years of history is an incredibly humbling and worthwhile experience.