South America, fourth largest of the Earth's seven continents (after Asia, Africa, and North America), occupying 17,820,900 sq km (6,880,700 sq mi), or 12 percent of the Earth's land surface. It lies astride the equator and tropic of Capricorn and is joined by the Isthmus of Panama, on the north, to Central and North America. The continent extends 7,400 km (4,600 mi) from the Caribbean Sea on the north to Cape Horn on the south, and its maximum width, between Ponta do Seixas, on Brazil's Atlantic coast, and Punta Pariñas, on Peru's Pacific coast, is 5,160 km (3,210 mi).

South America has a 2000 estimated population of 348 million, or 6 percent of the world's people. The continent comprises 12 nations. Ten of the countries are Latin: Argentina, Bolivia, Brazil, Chile, Colombia, Ecuador, Paraguay, Peru, Uruguay, and Venezuela. Two of the nations are former dependencies: Guyana, of the United Kingdom, and Suriname, of The Netherlands. South America also includes French Guiana, an overseas department of France. Located at great distances from the continent in the Pacific Ocean are several territories of South American republics: the Juan Fernández Islands and Easter Island (Chile) and the Galápagos Islands (Ecuador). Nearer the coast, in the Atlantic Ocean, is the Fernando de Noronha Archipelago, which is a Brazilian territory, and, farther south, the British dependency of the Falkland Islands, which is claimed by Argentina as the Islas Malvinas. The coastline of South America is relatively regular except in the extreme south and southwest, where it is indented by numerous fjords.

South America consists of four upland provinces, extending inland from the coasts, and, between them, three lowland provinces. The northern and western fringes are dominated by the Andes Mountains, the second highest mountain range in the world. Most of the eastern coast is fringed by the broader—and generally less elevated—highland areas of the Guiana and Brazilian massifs and the Patagonian Plateau. The main lowland is the vast Amazon Basin in the equatorial part of the continent; it is drained by the Amazon River, the world's second longest river. The Orinoco River drains a lowland in the north; to the south lies the Paraguay-Paraná basin. The lowest point in South America (40 m/ 131 ft below sea level) is on Península Valdés in eastern Argentina, and the greatest elevation (6,960 m/22,834 ft) is atop Aconcagua in western Argentina, the highest peak in the Western Hemisphere.

The oldest and most stable structural element of the continent is the shield area of the Brazilian and Guiana highlands of the east and northeast. It comprises a Precambrian (before 570 million years ago) complex of igneous and metamorphic rocks. In most places the shield is overlaid by sedimentary rocks, mostly of Paleozoic age (570 million to 225 million years ago), although some areas of younger basalts occur, notably in southern Brazil. Fossils found in the Brazilian Highlands offer evidence of continental drift, indicating that in the Permian period the continent was linked to Gondwanaland, a great landmass incorporating Africa and Asia.

The complex that underlies the Patagonian Plateau is largely mantled by sediments deposited in the Mesozoic Era (225 million to 65 million years ago) and Tertiary Period (65 million to 1.6 million years ago) and by basalts of recent formation.

Material eroded from the old shield areas contributed to the thick deposits of sediments in the surrounding seas. These sedimentary formations were uplifted repeatedly in the Mesozoic Era to form the coast ranges of Chile and southern Peru and the higher and more extensive Andes. This mountain-building process, which continued through the Tertiary Period, was accompanied by intrusions of magma (molten rock) and by the formation of volcanoes. Volcanic and seismic activity continue all up and down the continent's western rim. The glaciers of the southernmost Andes are remnants of the great ages of glaciation of the Quaternary Period (beginning 2.5 million years ago). The erosion of the highlands continues to contribute sediments to surrounding lowlands.

Rising abruptly from the northwestern and western coasts of the continent are the Andes. They consist of a single chain in Venezuela, in the north, and through much of Chile and Argentina, in the south, but the central part of the mountain system consists of two or three parallel axes of mountains, known as cordilleras, or ranges. In southwestern Bolivia and southern Peru, a region of large intermontane plateaus called the Altiplano separates the ranges. In Peru and Argentina the ranges are separated by relatively narrow but deep valleys. Among the two dozen peaks that exceed an elevation of 17,000 ft (equivalent to 5,182 m) are a number of active volcanoes located in south central Chile, southern Peru and Bolivia, and Ecuador.

The vast uplands of Guiana, in the northeast, and of Brazil, in the east, have rolling to hilly surfaces, with broad plateaus and high mesas. The plateaus are higher and less broad in the highlands of Guiana. In the Brazilian Highlands, the greatest relief occurs in mountains that lie along the eastern coast, in many places rising abruptly from the sea. In general, the rocks of these uplands have weathered into infertile, reddish soils. Fertile soils derived from basaltic rocks are found in many valleys, however. To the south is the less elevated and relatively flat Patagonian Plateau (see Patagonia). Although soils here are generally fertile, climatic constraints limit their agricultural usefulness.

The northernmost of the continent's principal lowland areas is the Orinoco Basin, which includes the Llanos—a region of alluvial plains and low mesas—and a vast system of valleys that converge toward the Amazon between the Caquetá and Madeira rivers. The Amazon Basin itself is a region of slightly rolling terrain. Farther south are the shallow valleys and flat plains of the Gran Chaco and the Pampas, both of which merge with the swampy floodplains of the Paraguay and Paraná rivers.

The greater part of South America is drained to the Atlantic Ocean by three river systems: the Amazon, Orinoco, and Paraguay-Paraná. Each of these large rivers also provides access to the interior. The smaller São Francisco River drains northeastern Brazil. Numerous lesser rivers drain the Caribbean and Pacific flanks of the Andes. The most important of these is the Magdalena River and its tributary, the Cauca River. This system, which drains north through Andean valleys in western Colombia to empty into the Caribbean Sea, has also provided a traditional access route to the interior. Scores of short Andean streams have sustained agriculture for centuries in Ecuador, Peru, Chile, and northwestern Argentina. Considerable hydroelectric power potential exists in the streams of the Andes and in those of the Guiana and Brazilian Highlands. The Mantaro Valley hydroelectric scheme in the Andes of Peru provides most of Lima's electricity.

South America has few large lakes. Many of the large permanent lakes are situated at relatively high elevations in the Andes. Among the largest are Lake Titicaca and Lake Poopó in Bolivia; Buenos Aires, Argentino, and Nahuel Huapí lakes in Argentina; and Lake Valencia in Venezuela.

South America is dominated by relatively warm climatic regimes. Spanning nearly the entire continent along the equator is a belt of humid tropical climate that grades to the north and south into broad zones where the length of the rainy season and the amount of rainfall diminish. These zones have wet summers and dry winters and are subject to prolonged droughts. Droughts are a particularly serious problem in northeastern Brazil and along the northern coast of Venezuela and Colombia. The areas of rainy tropical and tropical wet-dry climate extend along the Pacific coast of Colombia and Ecuador but are marked by a sharp southern transition into the arid climate of coastal Peru and northern Chile. In the northern half of South America only the Andes region has a cool climate. Temperatures decrease with increasing elevation, so that the tropical climate of the lowlands and lower slopes changes to subtropical and temperate climates at intermediate elevations, and finally to cold alpine climate at the mountain crests.

South of the tropic of Capricorn, South America has cool to cold winters and cool to warm summers. Southern Chile receives heavy precipitation, because of the cyclonic storms that move off the Pacific Ocean from the west. The storm frequency, greatest in winter, diminishes northward through Chile, resulting in a zone of Mediterranean-like climate, with mild, wet winters and warm, dry summers. This zone is bordered by desert, which extends along the coast as far north as Ecuador. Included in this region is the Atacama Desert, one of the driest places in the world. Subhumid and arid conditions prevail to the east of the southern Andes. In the Pampas and southern Brazilian Highlands, however, summers tend to be humid, and in the winter cyclonic storms may penetrate, bringing rain and chilly weather. Snow occasionally falls over the highlands, and frosts may spread north toward the tropic of Capricorn, causing extensive damage to crops.

The vegetation zones of South America correspond closely with the climatic zones. The areas of wet tropical climate have a dense cover of rain forest, or selva. The largest forest area in the world, this rain forest covers much of equatorial South America, including the Brazilian coast and the lower slopes of the Andes, and contains tropical hardwoods, palms, tree ferns, bamboos, and lianas. Open forests and brushlands are found in the areas of winter drought chiefly on the Venezuelan coast, in northeastern Brazil, and on the Gran Chaco. Between these drier areas and the rain forest are zones of tall grass (savannas, or campos) and of scrub and grass (campos cerrados). Mixed (containing both deciduous and evergreen trees) and deciduous forests occur in southern Brazil and along the slopes of the Andes. In Brazil the forest grades, to the south, into areas of rolling prairie interrupted by wooded hills. The Gran Chaco is characterized by grassy plains and open thorn scrub forest. The flat Pampas of east central Argentina is the largest midlatitude grassland of South America. To the south a zone of scrub steppe (monte) marks the transition to the low brush and bunch grass that cover the drier and cooler Patagonia region. Along the Pacific coast, the vegetation grades northward from forest to open woodland, to shrubs and grass in central Chile, and eventually to the scrub and desert vegetation that prevails into northern Peru and up to the mountain flanks.

South America, Central America, the lowlands of Mexico, and the West Indies may be classified as a single zoogeographic region usually called the Neotropical Region. Fauna is characterized by variety and a singular lack of affinity with the fauna of other continents, including North America north of the Mexican Plateau. Found throughout are families of mammals absolutely confined to the region, including two unique species of monkey, bloodsucking bats, and many unusual rodents. The region has only one kind of bear, the spectacled bear; no horses or related animals, aside from one species of tapir; and no ruminants, except lamoids (members of the camel family), which include alpacas, llamas, and vicuñas. Also characteristic of the continent are jaguar, peccary, giant anteater, and coati. Birds display still greater isolation and singularity. About 23 families and about 600 genera of exclusively Neotropical birds occur, as well as the greater part of other important families, such as those of the hummingbirds (500 species), tanagers, and macaws, together with a great variety of sea fowl. The largest birds include the rhea, condor, and flamingo. Reptiles include boas and anacondas; iguanas, caimans, and crocodiles are found in many areas. Freshwater fish are varied and abundant. Regional exclusiveness also characterizes insects and other invertebrates. On the whole, South American fauna is more local and distinct than that of any continent other than Australia; probably more than four-fifths of its species are restricted to its zoogeographic boundaries. The Galápagos Islands are the habitat of reptiles and birds that are unknown elsewhere, including the Galápagos giant tortoise, Darwin's finches, and the Galápagos penguin.

South America has diverse mineral resources, many of which have not been extensively exploited. Mineral deposits are widely distributed, but certain areas of the continent are particularly renowned for their wealth. In the Andes placer gold has been worked in various areas since before the colonial era. The mountains between central Peru and southern Bolivia produced silver and mercury in the colonial era, and industrial minerals such as copper, tin, lead, and zinc today. Copper is worked at large deposits in northern and central Chile and in central and southern Peru. A highly mineralized area containing bauxite, iron ore, and gold lies between Ciudad Bolívar and northern Suriname, near the northern margin of the Guiana Highlands. In east central Brazil rich gold and diamond strikes occurred in the colonial era, some of these mines are still producing. Although South America is a major producer of rare metals, the large reserves of high-grade iron ore and smaller reserves of bauxite are more important to the emerging industrial power of the continent.

South America is lacking in large coal reserves. Coal is found in scattered and relatively small deposits in the Andes and in southern Brazil. Coal has been an important fuel for industry and transportation primarily in Chile, Colombia, and Brazil. Petroleum, however, is widely distributed. Most of the continent's reserves of petroleum and natural gas lie in structural basins located mostly along the eastern margins of and in the Andes, from Venezuela to Tierra del Fuego. The largest known fields are in the Lake Maracaibo area of Venezuela. Other deposits occur in northern Colombia, Ecuador and Peru, south of the Andes in eastern and central Venezuela, and just east of the mountains in Colombia, Ecuador, Peru, Bolivia, Argentina, and Chile.

South America's overall population has been increasing rapidly, especially in the developing tropical countries, and urban populations have increased greatly in all parts of the continent. Immigration to South America has been minimal since 1930. Internal migration has been of great significance, however, increasing the concentration of people living on the continent's periphery, while vast areas of the interior remain sparsely populated. The overall population density is 20 persons per sq km (52 per sq mi), but more than half the continent has a population density of fewer than 2 persons per sq km (5 per sq mi).

Although South America's population has a diverse ethnic heritage, its principal elements are the Native Americans and the descendants of Spaniards, Portuguese, and African blacks. The racial spectrum produced by mixing the various groups is broad. Most evident in South America are the mestizos, people of Iberian and Native American ancestry; people of mixed Iberian and black ancestry are less numerous, and the number of people of mixed Native American and black ancestry is smaller yet. The Native Americans are most numerous in the highlands of the central Andean republics. People of Spanish descent are relatively more numerous in Argentina and Uruguay than elsewhere. In Brazil, the Portuguese are the predominant Iberian element, and the black and mulatto groups are more numerous than in any other South American country. In the Guianas and coastal Colombia and Ecuador, the number of blacks is also large.

The steady but relatively modest flow of Iberians into South America during the colonial era and in the century and a half since independence was augmented between the late 19th century and 1930 by the entry of several million Italians, chiefly into Argentina, Brazil, and Uruguay. Smaller numbers of Germans, Poles, and other European nationals also arrived. Although many of the new European immigrants were engaged in rural labor and tenant farming in Argentina and Brazil, many Germans and Italians and fewer other Europeans established agricultural colonies. German colonists, for example, settled in south central Chile. Other new immigrants gravitated toward the cities, where they contributed substantially to the workforce and entrepreneurial sectors. Several non-European groups, such as Syrians and Lebanese, settled in large numbers also. The greatest numbers of Asian immigrants during the late 19th century came from India, Indonesia, and China; most of these entered British Guiana and Dutch Guiana as indentured laborers after the abolition of slavery. Particularly since 1900, however, appreciable numbers of Japanese have settled in southeastern Brazil. Japanese settlements also exist in Paraguay, Bolivia, and northern and northeastern Brazil.

South America's population more than doubled between 1960 and 2000. About one-half of the continent's people live in Brazil. Six other countries claim nearly 45 percent of the remaining population: Colombia (11.5 percent), Argentina (10.7 percent), Peru (7.8 percent), Venezuela (6.8 percent), Chile (4.4 percent), and Ecuador (3.7 percent). Average population growth rates approached 2.4 percent per year between 1965 and 1990, although Argentina and Uruguay have grown more slowly, as, to a lesser extent, have Chile and Bolivia. The growth in population is due largely to natural increase, the birth rate being 21 per 1,000 people and the death rate 8 per 1,000 in 2000. In many areas death rates have been declining substantially for decades, whereas high birth rates only recently have shown a downward tendency. The estimated number of people under the age of 15 in 2000 was 31 percent, while the median age was 25.1 years in 2000.

Natural increase and migration from provincial areas have caused urban populations to grow by up to 4 percent a year. In Argentina, Chile, and Uruguay, the rate of urban growth has slowed, but in the tropical countries, cities are growing with great rapidity. In the most urbanized of the larger countries—Argentina, Chile, Uruguay, and Venezuela—at least 80 percent of the population lives in urban centers; in the least urbanized—Bolivia, Ecuador, and Paraguay—less than 65 percent of the population is classified as urban.

Spanish is the official language of 9 of the 13 political entities on the continent. Portuguese is the official language of Brazil; English, of Guyana; Dutch, of Suriname; and French, of French Guiana. Among the scores of Native American languages, Quechua, Aymara, and Guaraní are spoken by the largest numbers of people. The speakers of Quechua (7.6 million in 1998) are primarily in the central Andean highlands, and the speakers of Aymara (2.1 million in 1998) in the highlands of Bolivia, Chile, and Peru. Guaraní is an official language of Paraguay, along with Spanish.

South America is unusual among the continents for its religious homogeneity. About 90 percent of the population is Roman Catholic. Most of the Protestants are in Brazil and Chile; the remainder are widely distributed, primarily in urban centers. The Jews of South America also tend to be urban dwellers and are widely distributed; about three-fourths are in Argentina and Brazil, and more than 10 percent are in Uruguay and Chile. Hindus, Muslims, and Buddhists are concentrated in Guyana and Suriname. The Roman Catholic faith was brought to the continent by the Spaniards and Portuguese during the Spanish conquest. Protestantism is a reflection of later European immigration and of missionary activity begun in the 19th century. North American evangelical groups were particularly active in the 20th century.

Historically a colonial area, economically dependent on the export of agricultural and mineral commodities, South America has experienced growth and diversification in most of its economic sectors since the 1930s. After World War II (1939-1945) national policies of import substitution (the local manufacture of formerly imported goods) reshaped industry. The benefits of this rapid economic development have not spread evenly but have accrued more to the leading cities and their environs. The development of free trade, beginning in the late 1960s with the Andean Pact and continuing into the 2000s with the Southern Cone Common Market (MERCOSUR) and the North American Free Trade Agreement (NAFTA), has greatly improved South America's economic prospects.

Most crop and livestock production in South America is for home consumption and domestic markets. Nevertheless, revenues from agricultural exports are very important in many South American countries. The processing, internal marketing, and exporting of agricultural products account for a substantial part of commercial and manufacturing activity. Although agriculture, together with hunting, fishing, and forestry, accounted for about 12 percent of the gross domestic product (GDP) within the continent in the 1990s, it accounted for more than 30 percent of the labor force in Bolivia, Paraguay, Peru, and Ecuador, between 20 percent and 30 percent in Colombia, Brazil, and Guyana, and less than 20 percent in Suriname, Chile, Uruguay, Venezuela, Argentina, and French Guiana.

The most intensive forms of commercial agriculture are concentrated near cities. Perishables, such as vegetables, fruits, and dairy items, are the principal products here. The production of staples such as root crops, beans, and corn is more dispersed. In many areas these crops are raised by subsistence farmers under unfavorable climatic or soil conditions. Wheat and rice tend to be produced wherever conditions are most suitable. The nonexport beef-cattle industry is dispersed widely; the raising of beef cattle for export is of particular importance in Argentina, Uruguay, Paraguay, and Colombia. Export-oriented agriculture is pursued in the tropical areas and midlatitudes, where arable land and access to ports are optimal. Among the tropical crops, coffee is the most important. It is produced in the highlands, chiefly in southeastern Brazil and in west central Colombia. Cacao is important in eastern Brazil and west central Ecuador. Bananas and sugarcane are produced throughout the tropics, mostly for domestic markets. Bananas are grown for export in Colombia and western Ecuador; sugar is produced for export in coastal Peru, Guyana, and Suriname. Cotton has been produced for export for many decades in coastal Peru. Cotton and sugarcane are also raised (both for export and domestic markets) in northeastern and southeastern Brazil. In southeastern Brazil soybeans have, since the 1970s, become an important export crop. Soybeans are less important in Argentina, where fertile prairie soils have long supported grain and livestock industries of worldwide importance. Argentine wheat, corn, linseed, beef, mutton, hides, and wool are important items of international trade. Uruguay has a long-standing export trade dominated by wool and hides.

Although the continent is 50 percent forested and is surrounded by seas rich in marine life, the forestry and fishing industries in most South American nations are small and oriented toward domestic markets. Some tropical hardwoods and softwoods are exported, however, much of the wood coming from the Amazon Basin, where large tracts of forest are being cleared for conversion into range and cropland. Also exported is pine lumber from southern Brazil and south central Chile, together with some pulpwood. Significant areas of commercial forest have been planted in Chile and Brazil. The widespread planting of eucalyptus trees for firewood, for timbering, and for use in rough construction has historically been important.

South America's most important commercial fisheries are the Pacific coastal waters. Large amounts of anchovies for fish meal are caught off the Peruvian and Chilean coasts, although overfishing has depleted recent harvests. Tuna are taken off the Ecuadorian and Peruvian coasts. Crustaceans are an important catch in Chilean, Brazilian, and Guianese waters.

Most mining for export is on a large scale. The long history of foreign corporate control of South American mining operations is waning because of national political pressures. Petroleum, copper, bauxite, and iron ore are the principal commodities in value and volume, but mineral exports are greatly diversified. South America is an important world producer of lead, zinc, manganese, and tin. Although all South American countries have some mineral production, Venezuela's oil and gas account for more than half the total value of the continent's output. Mineral production is of great importance to several national economies. Venezuela's exports are dominated by crude and refined petroleum, and derivatives, while the dependence on mineral exports is somewhat less in Suriname, Bolivia, and Chile. Peru and, in recent years, Ecuador, have relied heavily on the sale of minerals. Such exports generate government revenue, but mining contributes little to continental GDP and employment. Nevertheless, mineral commodities are important to the continent's growing industrial diversification.

By the late 1970s manufacturing accounted for at least 25 percent of South America's GDP, up from 20 percent in 1956, when it first exceeded in imp