Enfolded by the snow peaks of the Minshan mountain range, the Jiuzhai Valley in southeastern Sichuan protects one of China’s signature landscapes, in which dozens of exquisite blue lakes are cradled by miles of empty forested hills. Believed to be the shards of a mirror belonging to the Tibetan goddess Semo, the lakes derive their impossibly beautiful colour from beds of travertine limestone, combined with the presence in the glacial water of rare blue-green algae. The spectacle entices streams of visitors here in the autumn, when the lakes are framed by dazzling displays of yellow and red leaves.