Is the world's highest volcano hiding in plain sight on the Andes border?

Countries & Cities · Published 30 September 2026 Swipe more like this →

In short: Rising 6,893 metres above sea level, Ojos del Salado is the tallest volcano on Earth. Despite its stature, this dormant giant remained largely ignored by explorers for centuries, obscured by a dense cluster of neighboring peaks and a remote, arid landscape that feels more like a desolate moonscape.

Straddling the border between Argentina and Chile, Ojos del Salado is a complex massif rather than a single cone. It consists of over 20 overlapping craters, lava domes, and flows covering up to 160 square kilometres. Its extreme elevation and position near the Arid Diagonal of South America create a harsh, water-scarce environment. Because the equilibrium line for ice sits above the mountain's summit, it lacks substantial glaciers, leaving the surface dominated by talus slopes, desert plains, and wind-driven sand fields.

The mountain’s history is defined by its geological complexity and its surprising lack of recent activity. While it was volcanically active during the Pleistocene and Holocene, its last confirmed eruption occurred around 750 CE. Though observers reported steam emissions in 1993, the volcano is considered dormant. Its summit crater hosts the world's highest lake, a permanent body of water sitting at approximately 6,500 metres. This lake is fed by permafrost and snowfields, and nearby fumaroles—first noted by Polish climbers in 1937—continue to emit sulfurous fumes, hinting at the hydrothermal activity still pulsing beneath the surface.

For decades, the mountain’s true identity was shrouded in confusion. Early boundary commissions and explorers often misidentified it, and it was not until the 1937 expedition by Jan Alfred Szczepański and Justyn Wojsznis that the summit was officially reached. Even then, the loss of their records during World War II delayed widespread recognition. Today, Ojos del Salado is recognized as the second-highest peak in the Andes, surpassed only by Aconcagua. While it remains a low-risk site for future eruptions, its unique combination of extreme altitude, buried ice, and high-altitude microbiology continues to fascinate researchers studying the limits of life and the evolution of the Central Volcanic Zone.

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