A continuous volcanic-tectonic wall running from Venezuela to Tierra del Fuego. Extreme elevation, narrow valleys, and high plateaus (especially the Altiplano) create isolated agricultural basins linked by mountain roads rather than rivers. This geography favors vertically organized societies — mastering multiple climate zones stacked on top of each other — and produces centralized, infrastructure-heavy civilizations like the Inca. The Andes serve as South America’s civilizational spine and its primary engine of state formation.
