A must do!!
If you are going to China, you cant say that you were in Beijing if werent in the Great Wall. I was there on April and it was very cool, it was a privilige standing there and after you've kinda climbed about 5 miles up, you stop and breathe and have a spectacular view of the great wall, i thanked God for being there, and i can't wait to get my family there... i went to the Badaling section, i've heard comments that some other people think its too crowded, too touristy, but its so great to be sharing this experience with people all over the world, taking pictures with each other, its so great. I would recommend you to go there with comfortable clothes and shoes, take your cameras and try to really live it amongst the other visitors.. A unique experience!!!