Huanglong is a 3.6-kilometre staircase of golden stone with thousands of pools set into it, stepping down an alpine valley in northern Sichuan. From above the whole run of terraces looks like a scaled body winding down the mountain, which is where the name comes from: yellow dragon. Each basin holds a slightly different colour — jade, amber, ice-blue — and the rims between them are pale limestone, so the water reads as a set of separate panes. The stone is travertine, dropped out of calcium-rich spring water as it flows and cools. At the valley's head, 3,576 metres up, the Five-Colour Pond gathers roughly 693 basins into one shimmering sheet, the highest cluster of travertine pools in the world. Above it stands Xuebaoding, at 5,588 metres the highest peak of the Min Mountains, usually under snow.
Getting up there means a slow climb on wooden boardwalks through pine and larch forest. The air thins fast near 3,500 metres, and oxygen bottles are sold at the gate for a reason. Beneath the clear water lie pale limestone rims, fallen trunks and bright green moss. Where the boardwalk ends stands a small Ming-era Taoist temple built for the dragon of the legend. In autumn the slopes catch fire in red and gold and the warm leaves meet the cold turquoise below, though a single cold snap can strip the trees in days. The colours run deepest when the pools are brimming after rain, and thinnest at the end of a dry spell. The upper end of the valley is the quietest stretch of the walk, where water slips from one terrace to the next and the snow line stands just above you. A cable car now covers most of the climb.