The Huanglong or Yellow Dragon carst caves are part of the Wulingyuan Scenic Area, a World Heritage Site in Zhangjiajie city in China's Hunan province. With a geologic history of 380 million years, the caves have always fascinated tourists with their bizarre stone pillars and meandering river which turns into a fantastic underground maze. Entrance is around 80 yuan (guide included) and the caves are illuminated with colorful lights to add a touch of magic to the tour.[Photo:sina.com.cn]