Mexico's Sierra Madre Occidental in the west rises to 3,158 m at Cerro Mohinora, a volcanic chain from Miocene eruptions 25 million years ago with pine-oak forests covering 200,000 km². The Sierra Madre Oriental peaks at 3,700 m at Cerro San Rafael, parallel to the Gulf coast. Trans-Mexican Volcanic Belt features Popocatépetl (5,426 m)—active—and Pico de Orizaba (5,636 m), Mexico's highest. Formed by subduction, the Yucatán Peninsula's low karst averages 100 m with cenotes up to 100 m deep. Baja California peninsula's Sierra de la Laguna reaches 2,000 m. This topography includes 181 protected areas with monarch butterflies and jaguars.
