Ojos del Salado

A 6,893-metre stratovolcano on the border between Argentina and Chile, in the Andes of the Atacama region. Ojos del Salado is the highest volcano in the world and the second-highest peak in the Western Hemisphere after Aconcagua, 600 kilometres south. The name in Spanish means "eyes of the salty one" — a reference to the salt deposits that fill the small high-altitude lakes on the upper mountain. One of these lakes, at 6,390 metres, is the highest body of water on Earth.

The first ascent was made in 1937 by a Polish expedition. Jan Alfred Szczepański and Justyn Wojsznis reached the summit on February 26 — early in the era of South American mountaineering, before commercial expeditions or substantial infrastructure. The climbing route they took, the Northwest Ridge from the Atacama side, is essentially the standard route today. The mountain is technically straightforward — no glaciers, no significant ice, and a final summit pyramid that requires light scrambling but no roped climbing.

What separates Ojos del Salado from a long high-altitude trek is the location. The Atacama desert is the driest non-polar place on Earth. The approach to the mountain crosses landscapes that are functionally Martian — red rock, salt flats, no vegetation, no water. The mountain itself receives almost no precipitation. Snow is rare even at the summit. The altitude is extreme, and the desert at that altitude is a particular kind of demanding. Acclimatization in dry, windy conditions at low oxygen creates physiological stress that climbers familiar with humid Himalayan acclimatization have sometimes underestimated.

The mountain is climbed by perhaps several hundred people per year. The fatality rate is low — significantly lower than mountains of comparable altitude in Asia — but the rescue infrastructure is minimal. Climbers who get into trouble on Ojos del Salado are frequently several days from the nearest road. The remoteness is part of what the mountain is.