*'''The Andean region''' in the southwest spans 28% of the national territory, extending over . This area is located above  altitude and is located between two big Andean chains, the ''Cordillera Occidental'' ("Western Range") and the ''Cordillera Central'' ("Central Range"), with some of the highest spots in the Americas such as the Nevado Sajama, with an altitude of , and the Illimani, at . Also located in the Cordillera Central is Lake Titicaca, the highest commercially navigable lake in the world and the largest lake in South America; the lake is shared with Peru. Also in this region are the ''Altiplano'' and the ''Salar de Uyuni'', which is the largest salt flat in the world and an important source of lithium.