Good outdoor places to travel in China ?

Hi,

I am a student currently in China and I will have some free times to travel in China.

I was wondering if you knew cool outdoor places in China that are nice to see when you travel alone. Furthermore, I am currently studying in Wuhan so if it's close it's better.

I know zhangjiajie is nearby, do you know if it's enjoyable to go there by yourself ?

Thanks in advance.