[Source]
Heaven's Gate Mountain is a cave natural arch eroded through a karst syncline. It is located about 8 km south of the city of Zhangjiajie (formerly Dayong) in northern Hunan Province, China. It is accessed from Zhangjiajie by what may be the world's longest skytram (7.5 km) that leads to a bus ride on a very winding road, followed by a set of stairs with 999 steps.[Source]
