Lusaka is the capital and largest city of Zambia. One of the fastest developing cities in southern Africa, Lusaka is in the southern part of the central plateau at an elevation of about 1,279 metres (4,196 ft). As of 2010[update], the city's population was about 1.7 million, while the urban population is 2.4 million. Lusaka is the centre of both commerce and government in Zambia and connects to the country's four main highways heading north, south, east and west. English is the official language of the city, but Nyanja and Bemba are also common.