Bolivia presents a sharp contrast between high, bleak mountains and plateaus in the west and lush, tropical rain forests in the east. In the southeast it merges into the semiarid plains of the Gran Chaco. The Andes mountain system reaches its greatest width in Bolivia. Two cordilleras, the western one tracing the border with Chile and the eastern running north and south across the center of the country, are divided by a high plateau (altiplano), most of it 12,000 ft (3,660 m) above sea level—barren, windswept, and segmented by mountain spurs.
Despite the harsh conditions the altiplano is the population center of Bolivia. Many sections for want of drainage have brackish lakes and salt beds, notably the extensive Salar de Uyuni in the south. In the north are Lake Titicaca, which Bolivia shares with Peru, and Lake Poopó. This region, world famous for its breathtaking scenery, was the home of one of the great pre-Columbian civilizations. Well known are the ruins of Tiahuanaco.
The eastern mountains, consisting of three major ranges, rise to the cold, forbidding heights of the Puna plateau (as high as 16,000 ft/4,880 m) and in the north to the snowcapped peaks of Illimani (21,184 ft/6,457 m) and Illampú (21,276 ft/6,485 m). In these mountains lies the source of the exploited wealth of Bolivia—its minerals. Tin is by far the most important product, but silver was once the chief metal, and tungsten, copper, wolframite, bismuth, antimony, zinc, lead, iron, and gold are also mined. The names of some mining towns, notably Potosí and Oruro, are world famous.
From the mountains, headstreams cut eastward, carving deep gorges and fingerlike valleys. In these valleys are some of Bolivia's garden spots—Sucre, Cochabamba, and Tarija. Santa Cruz de la Sierra and La Paz are the two main cities of tropical Bolivia. In the eastern foothills headstreams gather to form the Beni, the Guaiporé, and the Mamoré (tributaries of the Madeira, in Brazil), which flow through the torrid, humid yungas, covered with dense rain forests, and inhabited mainly by indigenous South Americans. The region is the most fertile in the country, yielding cacao, coffee, and tropical fruits, and in the early 20th cent. was a major source of wild rubber and quinine. Some of the more accessible valleys, with luxuriant scenery and a pleasantly warm climate, have become popular Bolivian resort areas.
Of the indigenous people, about 30% are Quechua and 25% are Aymara, but the citizens of European descent (some 15% of the people) or mixed European and native ancestry (about 30% of the population) have historically maintained economic, political, and social hegemony, but this has been challenged by Evo Morales, who was elected president in 2005, and by the constitution adopted in 2009. Spanish and 36 indigenous languages including Aymara, Quechua, and Guaraní are all constitutionally recognized as official languages. A few indigenous groups have remained isolated from European culture. Most of the population is Roman Catholic, although many people of indigenous descent retain the substance of their pre-Christian beliefs. There is also an evangelical Protestant minority.