altiplano (ălˌtĭpläˈnō) [key], high plateau (alt. c.12,000 ft/3,660 m) in the Andes Mts., c.65,000 sq mi (168,350 sq km), W Bolivia, extending into S Peru. The altiplano is a sediment-filled depression between the Cordillera Oriental and the Cordillera Occidental. Its lowest point is occupied by Lake Titicaca, the largest high-altitude lake in the world. The lake is drained by the Desaguadero River south across the altiplano into Lake Poopó. The sparsely vegetated region receives little precipitation and has several large salt flats. The bleak plateau has a cool climate throughout the year. Corn and wheat are the principal crops there. Mining is the chief industry in the mineral-rich plateau. One of the world's most densely populated areas, the altiplano contains most of Bolivia's inhabitants; La Paz, the capital, and Oruro are the largest cities. A rail line runs across the altiplano.