what geographical feature limited contact between sub-saharan africa and the outside world
Sub-Saharan Africa Since probably 3500Â BCE,[4][5] the Saharan and Sub-Saharan regions of Africa have been separated by the extremely harsh climate of the sparsely populated Sahara, forming an effective barrier interrupted by only the Nile in Sudan, though the Nile was blocked by the river's cataracts. The Sahara pump theory explains how flora and fauna (including Homo sapiens) left Africa to penetrate the Middle East and beyond. African pluvial periods are associated with a Wet Sahara phase, during which larger lakes and more rivers existed.[6]
History of Kenya By 1850 European explorers had begun mapping the interior.[18] Three developments encouraged European interest in East Africa in the first half of the 19th century.[19] First, was the emergence of the island of Zanzibar, located off the east coast of Africa.[19] Zanzibar became a base from which trade and exploration of the African mainland could be mounted.[19] By 1840, to protect the interests of the various nationals doing business in Zanzibar, consul offices had been opened by the British, French, Germans and Americans. In 1859, the tonnage of foreign shipping calling at Zanzibar had reached 19,000 tons.[17] By 1879, the tonnage of this shipping had reached 89,000 tons. The second development spurring European interest in Africa was the growing European demand for products of Africa including ivory and cloves. Thirdly, British interest in East Africa was first stimulated by their desire to abolish the slave trade.[20] Later in the century, British interest in East Africa would be stimulated by German competition.