Trans-Kalahari Corridor South African border at Pioneer Gate/Skilpadshek. In South Africa it follows the N4 through Rustenburg to Pretoria. The route Walvis Bay–Windhoek–Lobatse–Pretoria–Maputo is route number 40 in the Southern African Development Community Regional Trunk Road Network. Trans-Kalahari Corridor The Trans-Kalahari Corridor is a paved highway corridor that provides a direct route from Walvis Bay and Windhoek in central Namibia, through Botswana, to Johannesburg and Pretoria in Gauteng province in South Africa. It initially cost approximately 850 million Namibian dollars (US$115 million) and was officially opened in 1998. The corridor also includes railway lines from Walvis Bay as far as Gobabis in
Kalahari Desert annual rainfall ranging from around 110 mm (close to aridity) to more than 500 mm in some areas of the north and east. During summer time in all regions rainfall may go with heavy thunderstorms. In the driest and sunniest parts of the Kalahari, over 4,000 hours of sunshine are recorded annually on average. In the Kalahari, there are two main mechanisms of atmospheric circulation, dominated by the Kalahari High anticyclone: There are huge subterranean water reserves beneath parts of the Kalahari; the Dragon's Breath Cave, for example, is the largest documented non-subglacial underground lake on the planet. Such reserves