Peru is a country in western South America. It is bordered on the north by Ecuador and Colombia, on the east by Brazil, on the southeast by Bolivia, on the south by Chile, and on the west by the Pacific Ocean. Peruvian territory was home to the Norte Chico civilization, one of the oldest in the world, and to the Inca Empire, the largest state in Pre-Columbian America. The Spanish Empire conquered the country in the 16th century and established a Viceroyalty, which included most of its South American colonies. After achieving independence in 1821, Peru has undergone periods of political unrest and fiscal crisis as well as periods of stability and economic upswing. Peru is a presidential representative democratic republic divided into 25 regions. Its geography varies from the arid plains of the Pacific coast to the peaks of the Andes mountains and the tropical forests of the Amazon basin. It is a developing country with a medium Human Development Index score and a poverty level around 40%. Its main economic activities include agriculture, fishing, mining, and manufacturing of products such as textiles. The Peruvian population, estimated at 28 million, is multiethnic, including Amerindians, Europeans, Africans and Asians. The main spoken language is Spanish, although a significant number of Peruvians speak Quechua or other native languages.