For Tianmen Mountain, Zhangjiajie is a fine location. For the rest of what you'd go to Zhangjiajie for (Golden Whip Stream nature hike; Yellow Dragon Caves; Baofeng Lake; and of course the Avatar-movie-type mountains, including "Hallelujah Mountain," stay in Wulingyuan. This is China, so don't expect Western standards …
I love Beijing! The air quality is terrible, the traffic is a nightmare, and all of the tourist sights are crowded, but I still love Beijing because there is so much to see and do. Locals are very friendly, but make sure you bring a Mandarin phrase book. I easily spent six days here.
The Terracotta Army and the walled city are fantastic, inside the walls are old markets which are fun, but two days max is enough for Xi'an. Outside the walls are dreary houses and factories. Other downers are the taxi drivers who refuse to use meters, just get out of the cab, the beggars which to a Westerner are very …
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The old town is a must place to see. Go to Shangri-La.
Wudang Shan (Wudang Mountain), the famous Taoist mountain, is close to Wuhan. Xiang Fan is a cool stopover to get to the mountain, about an hour away.
Shanghai is like any big city and it feels too Western. The old city and Yuyuan Gardens is touristy but beautiful and the area across the water from the Bund is beautiful. There is not much to do here, so after three days I was ready to move on.
Hangzhou is an absolutely beautiful city. I took it as a 4 day trip out of Shanghai where I was studying and fell in love.