WULINGYUAN, China: is noted for more than 3,000 quartzite sandstone pillars & peaks, many over 660 ft in height, along with ravines, gorges, streams, pools, & waterfalls. It features 40 caves, many with large calcite deposits, & two natural bridges, Xianrenqiao (Bridge of the Immortals) & Tianqiashengkong (Bridge Across the Sky). Wulingyuan forms part of the Wuling Mountain Range, which formed by 700 million years ago.