A vast upland plateau framed by the Sierra Madre ranges and crowned by the Trans-Mexican Volcanic Belt. High elevation moderates climate, increases agricultural productivity, and concentrates settlement into temperate basins. These enclosed highland valleys support dense populations, strong states, and monumental cultures — from Teotihuacan to the Aztec Triple Alliance. Geography favors centralization, imperial expansion, and long-term cultural continuity on a mountain-ringed core.
