Guatemala is mountainous with small patches of desert and sand dunes, all hilly valleys, except for the south coast and the vast northern lowlands of Petén department. Two mountain chains enter Guatemala from west to east, dividing Guatemala into three major regions: the highlands, where the mountains are located; the Pacific coast, south of the mountains and the Petén region, north of the mountains.
All major cities are located in the highlands and Pacific coast regions; by comparison, Petén is sparsely populated. These three regions vary in climate, elevation, and landscape, providing dramatic contrasts between hot, humid tropical lowlands and colder, drier highland peaks. Volcán Tajumulco, at 4,220 metres (13,850 feet), is the highest point in the Central American countries.
The rivers are short and shallow in the Pacific drainage basin, larger and deeper in the Caribbean and the Gulf of Mexico drainage basins. These rivers include the Polochic and Dulce Rivers, which drain into Lake Izabal, the Motagua River, the Sarstún, which forms the boundary with Belize, and the Usumacinta River, which forms the boundary between Petén and Chiapas, Mexico.
Guatemala's location between the Caribbean Sea and Pacific Ocean makes it a target for hurricanes such as Hurricane Mitch in 1998 and Hurricane Stan in October 2005, which killed more than 1,500 people. The damage was not wind-related, but rather due to significant flooding and resulting mudslides. The most recent was Tropical Storm Agatha in late May 2010, which killed more than 200.
Guatemala's highlands lie along the Motagua Fault, part of the boundary between the Caribbean and North American tectonic plates. This fault has been responsible for several major earthquakes in historic times, including a 7.5 magnitude tremor on 4 February 1976 which killed more than 25,000 people. In addition, the Middle America Trench, a major subduction zone lies off the Pacific coast. Here, the Cocos Plate is sinking beneath the Caribbean Plate, producing volcanic activity inland of the coast. Guatemala has 37 volcanoes, four of them active: Pacaya, Santiaguito, Fuego and Tacaná. Fuego and Pacaya erupted in 2010.
Natural disasters have a long history in this geologically active part of the world. For example, two of the three moves of the capital of Guatemala have been due to volcanic mudflows in 1541 and earthquakes in 1773.
Guatemala has 14 ecoregions ranging from mangrove forests to both ocean littorals with 5 different ecosystems. Guatemala has 252 listed wetlands, including five lakes, 61 lagoons, 100 rivers, and four swamps. Tikal National Park was the first mixed UNESCO World Heritage Site. Guatemala is a country of distinct fauna. It has some 1246 known species. Of these, 6.7% are endemic and 8.1% are threatened. Guatemala is home to at least 8,681 species of vascular plants, of which 13.5% are endemic. 5.4% of Guatemala is protected under IUCN categories I-V.
The Maya Biosphere Reserve in the department of Petén has 2,112,940 ha, making it the second-largest forest in Central America after Bosawas.