The iconic pillars of Zhangjiajie's Wulingyuan. The distinct geology found in central China's Hunan province makes it truly one of the world's most unique natural formations. According to UNESCO, "the site is dominated by more than 3,000 narrow quartz sandstone pillars, many over 200m high. Nestled within its towering peaks lie ravines and gorges with streams, pools and waterfalls, two large natural bridges, and some 40 caves. Impressive calcite deposits are a notable feature within these caves. In addition to the striking beauty of the landscape, including spectacular jagged stone peaks, luxuriant vegetation cover and clear lakes and streams, the region is also home to a number of endangered plant and animal species."