Botswana and 30°E. The country is predominantly flat, tending toward gently rolling tableland. Botswana is dominated by the Kalahari Desert, which covers up to 70% of its land surface. The Okavango Delta, one of the world's largest inland deltas, is in the northwest. The Makgadikgadi Pan, a large salt pan, lies in the north. The Limpopo River Basin, the major landform of all of southern Africa, lies partly in Botswana, with the basins of its tributaries, the Notwane, Bonwapitse, Mahalapye, Lotsane, Motloutse and the Shashe, located in the eastern part of the country. The Notwane provides water to the capital through
Kalahari Augrabies Extreme Marathon of 40 °C in the summer months and dropping to below 5 °C at night during the winter, presents a daunting challenge to the extreme athlete and determined adventurer alike. Known as the 'Big Daddy' in the South African running circles, the Kalahari Augrabies Extreme Marathon is event organised by Extreme Marathons, and has its place on the International Calendar of similar trail events. Participants run in the footsteps of the ancient Bushmen, through the fertile vineyards of the Orange River Valley (not in 2015), across rocky outcrops and into the desolate Great Kalahari Desert. Although the event is advertised