Bolivia (/bəˈlɪviə/; Spanish: [boˈliβja]; Quechua: Buliwya [bʊlɪwja]; Aymara: Wuliwya [wʊlɪwja]; Guarani: Volívia [ʋoˈliʋja]), officially known as the Plurinational State of Bolivia (Spanish: Estado Plurinacional de Bolivia), is a landlocked country located in western-central South America. It is bordered to the north and east by Brazil, to the southeast by Paraguay, to the south by Argentina, to the southwest by Chile, and to the northwest by Peru. Although only one-third of the country is located in the Andean mountain range, its largest city and principal economic centers are in the Altiplano.Before Spanish colonization, the Andean region of Bolivia was a part of the Inca Empire, while the northern and eastern lowlands were inhabited by independent tribes. The Spanish conquistadors arriving from Cuzco and Asunción took control of the region in the 16th century. During most of the Spanish colonial period, Bolivia was known as Upper Peru and administered by the Royal Court of Charcas. Spain built its empire in great part upon the silver that was extracted from Bolivia's mines.After the first call for independence in 1809, 16 years of war followed before the establishment of the Republic, named for Simón Bolívar, on 6 August 1825. Since independence, Bolivia has endured periods of political and economic instability, including the loss of various peripheral territories to its neighbors, such as Acre and parts of the Gran Chaco. It has been landlocked since it lost its Pacific coast territory to Chile in the War of the Pacific (1879–84), but agreements with neighbouring countries have granted it indirect access to the Pacific and Atlantic oceans.The country's population, estimated at 10 million, is multiethnic, including Amerindians, Mestizos, Europeans, Asians and Africans. The racial and social segregation that arose from Spanish colonialism has continued to the modern era. Before the revolution of 1952, native Bolivians were not permitted even to enter the principal plaza of La Paz, which contains the presidential palace and the congress.Many indigenous Bolivians today still seek to “pass” as mixed-race mestizos, whose social status is regarded as somewhat higher. The main language spoken is Spanish, although the Guarani, Aymara and Quechua languages are also common, and all four, as well as 34 other indigenous languages, are official.Modern Bolivia is constitutionally a democratic republic, divided into nine departments. Its geography varies from the peaks of the Andes in the West, to the Eastern Lowlands, situated within the Amazon Basin. It is a developing country, with a medium ranking in the Human Development Index and a poverty level of 53 percent. Its main economic activities include agriculture, forestry, fishing, mining, and manufacturing goods such as textiles, clothing, refined metals, and refined petroleum. Bolivia is very wealthy in minerals, especially tin.