Jiuzhaigou

Made a nature reserve in 1978 and opened to tourism in 1984, its name means valley of nine villages, after the Tibetan settlements that still stand there. Its hundred-odd turquoise and emerald lakes, with the trunks of ancient trees visible through water of extraordinary clarity, are formed as calcium carbonate dissolves and is laid down again, a geological process much like the one that colours Plitvice in Croatia. It was inscribed as a UNESCO World Heritage Site in 1992 and a Biosphere Reserve in 1997, and a magnitude 7.0 earthquake in 2017 temporarily damaged several of its lakes and waterfalls, forcing a partial closure and a considerable effort of geological and ecological restoration.