Kalahari

Kalahari, arid and semi-arid plateau region, southern Africa, in south-western Botswana, northern South Africa, and south-eastern Namibia, between the Orange River and the Okovango River valley to the north. The desert covers an area of about 260,000 sq km (100,000 sq mi). The Kalahari is part of a large sand basin stretching into Angola and Zambia in the north, through Botswana into Zimbabwe in the east, south to the Orange River in South Africa, and west to the highlands of Namibia. This basin has a total surface area of about 930,000 sq km (360,000 sq mi). The surface is mostly covered with red soil, except in the east where large patches of sand are found. When a heavy rain occurs, pans of water form in the extensive mud flats. The Kalahari was crossed in 1849 by the British explorer David Livingstone. In 1878-1879, many of the Boers who attempted to trek across the Kalahari on their way from the Transvaal to Angola died of thirst. The desert is inhabited by the Khoikhoi and San peoples. The region of Tsodilo, in the Botswanan part of the desert, contains one of the highest concentrations of rock art in the world; in 2001 Tsodilo was designated a UNESCO World Heritage Site.