Whilst living in Beijing I visited the Great Wall twice, at the same place "Mutianyu". If you ever go to China, I would recomend to try another place, as this one is a little too touristy for my liking.. but not half as bad as Badaling (the closest point to Beijing).
I visited once in summer, and once in autumn - and I loved seeing these two little boys, 1 Chinese and 1 American sat on the wall.. v cute!