Pastoruri Glacier

The authorised route climbs to 5,000 metres and stops beside the ice — equatorial sun above, glacial cold radiating off the face, air so thin each breath feels drawn through a straw. Markers along the trail show where the ice edge stood in years past. The glacier is retreating in real time, and it lets you watch.

Pastoruri, inside Huascarán National Park, is among the very few places on Earth to walk beside permanent ice under a tropical sun — and it has turned its own decline into the world's starkest classroom. The glacier has lost hundreds of metres since the 1980s, and the park's 'climate change route' marks the retreat year by year, a walk through recent planetary history with the diminished ice as its final exhibit. The drive up from Huaraz is a spectacle of its own: vicuña herds on the puna, and stands of Puya raimondii — the world's tallest flowering plant, a decades-long fuse of a rosette that blooms once, gigantically, and dies. Altitude is the honest tax on all of it; the day asks acclimatisation and gives perspective in return.