Ala-Köl is a lake at 3,532 metres in the Terskey Alatau mountains of eastern Kyrgyzstan, above the town of Karakol, held behind a wall of moraine with no river out, and it shifts from turquoise to grey to a faint pink with the light, which is why it is the goal of the most-walked trek in the country. The name means many-coloured lake, and the first outsider on record to reach it, the Russian traveller Putimtsoff in 1811, already remarked on the violent winds and the strangely coloured rocks in the water. The trek takes three days from Karakol. The lower trail climbs through spruce and fir forest, crossing icy meltwater streams on logs, before the path breaks above the treeline into a valley of boulders and yurt camps, and the last kilometres to the lake are a steep push over loose rock to a lip of moraine where the whole turquoise basin drops open below, ringed by bare snow-streaked peaks. Most people camp on the shore in a four-season tent, and the night above 3,500 metres is cold in any month.
The way on is the Ala-Köl Pass, near 3,900 metres, a lung-burning climb up scree from the lake to a notch with prayer flags where the lake lies behind and a new valley drops away ahead; from there the trail descends into the Altyn Arashan valley, green with meadow and pine, to a cluster of rustic yurt camps around hot springs, where the trek ends in a soak in a wooden hut with the mountains outside. Kyrgyzstan's Ala-Köl has a giant namesake next door, Lake Alakol in Kazakhstan, a salt lake roughly 1,750 times its size famous for flamingos, and the two are confused in every search. The lake is walked from June to September, with snow on the pass at either end of that, and horses carry gear for those who want them. Ala-Köl is a lake that changes colour while you watch, and the pass above it is where you look back.