The Andean Highlands and Altiplano

The Andes stretch approximately 7,000 to 8,900 kilometers along the western edge of South America, from Venezuela and Colombia in the north through Ecuador, Peru, Bolivia, Chile, and Argentina in the south, making it the longest continental mountain range in the world. The range formed, and continues to form, through the subduction of the oceanic Nazca Plate beneath the continental South American Plate, a process that generates both the Andes' extreme elevation — Argentina's Aconcagua, at 6,961 meters, is the highest peak in the Americas and the highest outside Asia — and the intense seismic and volcanic activity that defines the western margin of South America as part of the Pacific Ring of Fire. The 1960 Valdivia earthquake in Chile, measured at magnitude 9.5, remains the most powerful earthquake ever recorded by modern seismographs, a direct consequence of this same subduction zone.