The Great Wall of China is a must if you travel to China. An interesting aspect of most tours, are the other places that they take you along the way. On the way to the wall, the tour guide will stop at some kind of factory, give you a tour, and then drop you off in the showroom in hope that you'll buy something. The Great Wall tour guides and factory owners seem have to reached some kind of mutually beneficial agreement.
While it's obvious that the supplemental stops are nothing more than a ploy to get you to spend money, they can be interesting and informative. In this case, our tour guide took us to a jade factory, where they make jewelry, and all kinds of other ornamental items from this beautiful green stone. They show you how the items are made, explain all the aspects of the process, and then lead you directly to the showroom where they tempt you with all things jade.
While the Great Wall is definitely the highlight, the places they take you along the way are an important part of the experience. Just be careful, and don't get sucked in to buying a heavy (expensive) piece of jade that you don't really need, or want. Just look around and have a good time.