The population of Arica is made up of various long-established groups to the region, and other more recent arrivals settled at differing times. Among the long-established groups, the oldest consists of indigenous Amerindians, such as the Aymara, whose presence in the region is of several millennia. These are followed by the second oldest, the local colonial-era groups, which includes local mestizos (of mixed Spanish-Amerindian origin), local criollos (whites of colonial Spanish origin), and local afrodescendants of colonial-era slaves. The third oldest group consists of early post-colonial Chinese Chileans who first arrived as miners and rail workers in the 1890s.