Rainbow Mountain wore a cap of glacial ice until barely a decade ago; when the snow retreated around 2013, it uncovered a ridge banded in turquoise, gold, crimson and lavender that almost no one had seen. Known to the Quechua as Vinicunca, its colours are mineral, not painted: layers of ancient marine, lake and river sediment, each stained by a different element — iron oxide for the reds, sulphur-rich sandstone for the yellows, chlorite and copper for the greens. Laid down over millions of years, these beds were folded and tilted almost upright as the Andes rose, leaving a hillside striped in diagonal bands above 5,000 metres in Peru's Cusco region. It stands in the shadow of Ausangate, the 6,384-metre peak that Andean communities honour as a sacred apu, and within a year or two of the first viral photographs it ranked among the country's most visited sights, behind only Machu Picchu.
Reaching the colours is a lung-testing outing, not a hard climb. Most travellers leave Cusco before dawn, drive three hours into the highlands, then walk several kilometres from a trailhead already near 4,700 metres, often passing herders leading llamas across the thin air. At the top the whole painted ridge opens out, with the deep-red Valle Rojo folding away behind it beneath a rim of snow peaks. The altitude, not the distance, is the real hurdle, so two or three days acclimatising in Cusco first are essential. Sudden fame has brought pressure as well as crowds: in 2018 a mining company held a concession over the site, and only after local protest did it withdraw, after which the surrounding Ausangate range became a regional conservation area in 2019. Today the trail is looked after by the Andean communities of Pitumarca and Cusipata, who charge a small fee and keep the path.