Rainbow Mountain, Peru

Vinicunca — also called Montaña de Siete Colores, or Rainbow Mountain — rises to about 5,036 metres (16,522 ft) in the Andes of Peru's Cusco region, on the border between Cusipata and Pitumarca districts, on the road toward Ausangate. For most of its existence it was just another high Andean slope, kept hidden under a cap of glacier ice. That ice melted away in 2013, exposing the banded rock beneath, and within a couple of years word of the mountain's colours had spread; mass tourism arrived in the mid-2010s and the hike out to it is now one of the most popular day trips from Cusco.

The stripes come entirely from the mountain's mineral layers, laid down over different geological periods and now exposed side by side. According to Cusco's Cultural Landscape Office, the pink bands are red clay, mud and sand; the whitish sections are quartz-rich sandstone and marl high in calcium carbonate; the red comes from iron-bearing claystone dating to the Upper Tertiary; the green is phyllite and clay rich in ferromagnesian minerals; the earthy brown is a magnesium-bearing fanglomerate from the more recent Quaternary; and the mustard yellow is calcareous sandstone rich in sulphurous minerals. No single pigment or dye is involved — just rock chemistry stacked in visible layers. Reaching the mountain itself takes effort: from Pitumarca it's roughly a three-and-a-half-hour drive followed by a steep half-kilometre walk, and at over 5,000 metres, altitude acclimatisation beforehand is strongly recommended.

As a jigsaw, the banding that makes the mountain famous also makes it an unusually readable puzzle — each colour forms its own long, curving strip, so sorting pieces by hue first does most of the work before you even look at shape. The pale, cloud-streaked sky along the top edge and the muted scrubland in the foreground are the fastest sections to anchor, leaving the rainbow bands themselves as the satisfying centrepiece to slot in last, strip by strip.