European exploration of Africa 1840s, so that around the midpoint of the 19th century and the beginning of the colonial Scramble for Africa, the unexplored parts were now limited to what would turn out to be the Congo Basin and the African Great Lakes. This "Heart of Africa" remained one of the last remaining "blank spots" on world maps of the later 19th century (alongside the Arctic, Antarctic and the interior of the Amazon basin). It was left for 19th-century European explorers, including those searching for the famed sources of the Nile, notably John Hanning Speke, Sir Richard Burton, David Livingstone and Henry Morton
Slavery in Africa up to 17 million Africans slaves were transported by Muslim traders to the coast of the Indian Ocean, the Middle East, and North Africa. In 1814, Swiss explorer Johann Burckhardt wrote of his travels in Egypt and Nubia, where he saw the practice of slave trading: "I frequently witnessed scenes of the most shameless indecency, which the traders, who were the principal actors, only laughed at. I may venture to state, that very few female slaves who have passed their tenth year, reach Egypt or Arabia in a state of virginity." David Livingstone wrote of the slave trade: "To overdraw