. The department is almost entirely low-lying
Amazon rainforest. The climate is warm and damp, with average temperatures around [max.: , min.: ]. The rainy season is from December to March, when torrential rainfall causes rivers to swell and often overflow their banks. Annual precipitation can be as much as . The north-western boundary with the
Cusco Region is known as the Isthmus of Fitzcarrald, a series of small and low mountains that separate the
Madre de Dios River and the
Urubamba/
Ucayali River basins. Notable rivers in the
Madre de Dios River watershed are the
Inambari,
Tambopata,
Manu,
Tahuamanu,
Las Piedras (also known as Tacuatimanu River),
Heath,
Acre and
Los Amigos. Due to the vast size of the area and its low population density, rivers provide the best way of getting from one town to another. Human activity is invariably confined to riverbanks. A number of explorers have searched for the lost city of
Paititi in the jungle within the region. A new road that opened in early 2011 through the area will connect Brazil and Peru for trade, and change the isolation of this area. The only important highway is between the Peruvian cities of
Puerto Maldonado and
Cusco, away in the
Cuzco Department. It is part of the newly built Interoceanic Road between the Pacific and Atlantic Oceans, passing by the border town
Iñapari on the Acre river. Flights between Cusco and Puerto Maldonado remain the most common and quicker method of transport between the two. From Puerto Maldonado a road about long leads to the mining town Laberinto ("Labyrinth"). A second road is between the village of Pillcopata and Itahuania (into the Manú National Park). It is a roughly -long
single-track road that is hard to travel in the rainy season. It also has a dirt road to the native community of Infierno ("Hell"), where the
Ese'ejas (or
Guarayos) live. Their chief is Agustín Shapaja, who led the famous expedition (made into a TV special) to the Candamo. He was featured in the TV documentary
El Candamo, la Ultima Tierra sin Hombres (The Candamo, The Last Land without Men). ==Economy==