South America's population is one of the most mixed on Earth, and understanding that mix helps make sense of the continent. The four main threads are indigenous American peoples, Iberians (Spanish and Portuguese), Africans brought as slaves, and waves of post-independence immigrants — Italians, Germans, Lebanese, Japanese, and others. In most countries these threads have blended into something new, though in different proportions everywhere.
Indigenous peoples are most visible in the Andean countries. Bolivia has a majority indigenous population — Quechua and Aymara — and elected its first indigenous president in 2006. Peru and Ecuador both have large indigenous highland communities with distinct languages, dress, and traditions. Paraguay is unusual in that Guaraní, an indigenous language, is spoken by the majority of the population regardless of ethnicity. Across the Amazon basin, hundreds of smaller groups live in territories that in some cases have had little outside contact. Across the continent, an estimated 42 million people identify as indigenous.
The African presence is strongest in Brazil and along the Caribbean coast. Bahia, in northeastern Brazil, is sometimes called the most African city outside Africa — candomblé religion, capoeira, and the food of Salvador all trace directly back to West and Central Africa. Colombia's Pacific coast and its Caribbean port cities have strong Afro-Colombian communities. Venezuela and the Guianas also have significant African heritage. This history of slavery, brutal and not long past, shapes cultures, inequalities, and identities across the continent.
European immigration in the 19th and early 20th centuries transformed parts of the continent. Argentina and Uruguay received enormous waves of Italian and Spanish immigrants, which is why Buenos Aires sometimes feels more Mediterranean than Spanish colonial. Southern Brazil — the states of Santa Catarina and Rio Grande do Sul — has towns that still feel German or Italian. Chile's southern lake district has a strong German influence. Japanese immigration, particularly to Brazil in the early 20th century, left one of the largest Japanese diaspora communities outside Japan; São Paulo has a Japanese neighborhood, Liberdade, bigger than many cities.
What results from all this mixing is not a uniform culture but a mosaic. Colombians are warm and garrulous in a way that can take reserved travelers aback. Argentines are theatrical and proud and debate everything. Brazilians have a reputation for openness and physical ease — on the beach, in conversation, in music — that has some basis in reality. Andean cultures tend toward more formal courtesy. None of these generalizations hold in every city or village, but they're starting points. The continent will challenge them and confirm them in equal measure.