Jiuzhaigou is a valley in northern Sichuan where more than a hundred lakes step down the slopes, and the best of them are worth looking into rather than at. The water is cold, almost silt-free and loaded with dissolved lime, so you see all the way down. What is down there is a forest. You can pick out fallen trunks lying whole on the pale floor, and they do not rot: the lime-heavy water coats them in a mineral crust instead of letting them break down. The crust is why they stay legible: bark, branch stubs and the broken ends keep their shape under the mineral. The same load of lime keeps the colour moving: turquoise, emerald and gold shifting inside one pool at Five Flower Lake, where you lean over the rail and the drowned trees cross the bed below.
Long Lake, the highest and largest, lies in a broad basin with snow-streaked peaks closing the far end. No stream runs out of it — the water drains away underground — and the surface lies flat as glass. Mirror Lake earns its name in the windless hour after dawn, before the first breeze, when the water and its upside-down forest are hard to tell apart. At Nuorilang the river slides off a travertine cliff 320 metres wide and comes down in one broad sheet rather than a plunge, with a boardwalk carrying you along the lip. At Pearl Shoal it fans out over a calcified apron and splinters into spray, with a second boardwalk curling to the foot. The valley is named for the nine Tibetan villages along it, whose people tell the lakes as a mirror made of wind and cloud by the god Dago for the goddess Semo, and dropped. It broke into more than a hundred pieces, which is the number of lakes. The forest turns crimson and gold in the second half of October and doubles in the still water; in winter the falls hang as blue ice. Through all of it the trunks on the lake floors stay exactly as they went in.