Allison's Done-that list:
Great Wall of China
Traveled with a group of 10 people through GetYourGuide to the Great Wall, a tea shop, Tiananmen Square, and the Forbidden City. Took the cable car up to the wall and wandered around, then took toboggans down. You can walk for miles up there and there are not too many people if you find the right section of the wall!! Definitely a must see while in China and definitely worth the trek (its kind of far from Beijing).
Address: Great Wall of China, Huairou, China