Of course Mutianyu Great Wall.
It is situated in Huairou District of Beijing. It has a longer history and is less changed. It was appraised as the World Best of Beijing Tourism. In 2002, it was appraised as 4A grade scenic area and is the essence of Great Wall.
Mutianyu Great Wall Travel Area is surrounded with mountains and is of beautiful scenery. It enjoys a reputation of “Mutianyu surpassing others of Great Wall” and is the best scenic spot.
Mutianyu Great Wall Travel Area is equipped with complete devices and functions. Within the scenic area, there are cable cars, safe and conveniente. The cable car is reputed as “No. 1 Cable Car for Great Wall”. If you are brave, I recommend taking cable cars up and Slideway down. The slideway is very exciting.
Ps, no smoking in Great Wall. about 8 years ago
Do you want an easy day trip? More rugged terrain? To stay overnight? There are many sections of the Wall around Beijing and all of them offer something different. Some of the main ones are:
BADALING - the closest to Beijing and the most frequented by large tour groups. Gets very busy, especially on holidays and weekends. If the idea of a MacDonalds by the Great Wall offends you, then maybe give this one a miss!
MUTIANYU - as the poster mentions above, this section is a great choice. It's under 2 hours to get there, and while renovated and with plenty of visitors and vendors is still spectacular and well worth a visit. The "slideway" mentioned by Christina is actually a toboggan/luge. Super fun!
SIMATAI - you'll see this place mentioned in a lot of guide books and backpacker sites. There is a popular hike from JINSHANLING to this section. Sadly though, Simatai is closed until further notice as the local government is renovating the whole site to turn it into some kind of "hot springs resort". Sigh! You can still walk from Jinshanling to just over 1/2 way to Simatai.
GUBEIKOU - JINSHANLING - a good alternative to the above no longer available hike. Some sections of the wall are unrestored and crumbling. Steep steps and slopes so plenty of energy is needed for this hike. Most people with good fitness can complete it though by 5 hours.
Other sections still accessible easily from Beijing (with private transport) but a bit further away and less visited are JIANKOU and HUANGHUACHENG. But my favourite would have to be near the small village of SANCHA a few hours from Beijing... Kind of a "secret" and stunningly beautiful place! almost 8 years ago
Mutianyu is great. I was there in May, weather was beautiful then. I walked all the way up and climbed the stairs to the top of the Wall (as far as i was allowed to go). Coming down, i walked as well and i counted the total number of stairs of about 1100 stairs (from just below the wall to the ticket booth at the bottom). Took me 3 days to recover from the muscle ache in both my legs. almost 8 years ago