Guatemala, Central America's volcanic heart, features the Sierra Madre de Chiapas in the south, peaking at Tacaná (4,060 m)—shared with Mexico—with 37 volcanoes, including active Fuego (3,763 m) erupting since 2008. The Guatemalan Highlands average 1,500 m, dissected by Motagua Fault into grabens. Formed by Cocos-Caribbean subduction 20 million years ago, Lake Atitlán (1,300 m deep) fills a caldera. Northern Petén lowlands at 200 m host Mayan ruins amid limestone karst. Pacific coast rises to 3,000 m escarpments. This rugged terrain includes 21 protected areas with quetzal birds and howler monkeys in cloud forests.
