The jungle has approximately 1.9 million hectares stretching from southeast Chiapas into northern Guatemala and into the southern Yucatán Peninsula. The Chiapas portion is located on the Montañas del Oriente (Eastern Mountains) centered on a series of canyonlike valleys called the Cañadas, between smaller mountain ridges oriented from northwest to southeast. It is bordered by the Guatemalan border on two sides with Comitán de Domínguez to the southwest and the city of Palenque to north. The core of the Chiapas forest is the Montes Azules Biosphere reserve, but it also includes some other protected areas such as Bonampak, Yaxchilan, Chan Kin, Lacantum and the communal reserve of La Cojolita. Dividing the Chiapas part of the forest from the Guatemalan side is the Usumacinta River, which is the largest river in Mexico and the seventh largest in the world based on volume of water. The area has a mostly hot and humid climate (Köppen "Amg") with most rain falling from summer into fall, with an average of 2300 to 2600 mm per year. There is a short dry season from March to May when as little as thirty mm falls. The average annual temperature s 24.7C. The abundance of rain supports a large number of small rivers and streams many of which are fast moving and have waterfalls, such as the Agua Azul and the Lacanja waterfalls. The soils of the area are mostly clay and lacking phosphorus but sufficient to support a large diversity of plant species.