The most popular destination in the Great Wall is Badaling. Before entering the complex, your guide will tell you that you can climb either one of the two sides up the mountain. One side is steeper but offers greater views, the other is easier and more crowded. On both sides you will be surprised to find vendors every few yards. Ignore them. Although Badaling is not authentic, it was reconstructed 50 years ago, it is still the place I recommended to visit. It gives a better idea of what the Great Wall used to be. If you take the steep way, and get to the top, you will also see a part of the wall that has not been reconstructed.