It is a big river that flows through southern Africa to the Indian Ocean. Because it was undeveloped and unexplored, Africa was called “The Dark Continent Ein the 19th century. The first efforts to map the inland relied on sailing up rivers to their sources. Early explorers found the going difficult because of tropical diseases and wild beasts. The Zambezi River was especially dangerous due to the six meter long Nile Crocodiles lurking between its banks.