Zambia is a landlocked country located in southern Africa, between the Zambezi and Limpopo Rivers. The capital and largest city is Lusaka. Zambia is bordered by Zimbabwe to the north, Tanzania to the north-east, Malawi to the east and south, Botswana to the south-east and Namibia to the south. The climate is tropical in the north and generally temperate in the south. The official language of Zambia is English. The population of Zambia was estimated at just over 16 million as of 1 January 2011. The majority of people are Christian, with a small percentage following traditional beliefs. The economy is based mainly on agriculture, with coal and copper being exported.