Nevado Ojos del Salado is a dormant complex volcano on the Argentina–Chile border in the Andes and the highest volcano on Earth, reaching 6,893 metres above sea level.
The mountain sits in one of the world’s driest regions, near the Arid Diagonal of South America, where extreme aridity prevents substantial glacier formation or permanent snow cover. Despite these desiccated conditions, a permanent crater lake roughly 100 metres across sits at 6,480 to 6,500 metres elevation within the summit crater — the highest lake of any kind in the world. The upper slopes consist of overlapping lava domes, lava flows and volcanic craters spread across 70 to 160 square kilometres. Ojos del Salado was volcanically active through the Pleistocene and Holocene, primarily producing lava flows in two phases; its last eruption occurred around 750 CE, though steam emissions in November 1993 may have marked another event. The first recorded ascent was made in 1937 by Polish climbers Jan Alfred Szczepański and Justyn Wojsznis. Mid-20th-century debates over whether Ojos del Salado or Aconcagua held the title of South America’s highest peak were eventually settled in favour of Aconcagua.
