Huanglong Dong (Yellow Dragon Cave) in Zhangjiajie is a karst cave similar to the Qiuxiang one in Kunming. It is only two-thirds open to the public. A visit there will include an eight-minute boat-ride in a river within the cave and a climb of several hundred steps up four sections to exit it. What really captured my attention is a stalagmite that has been around for 960 million years!