Africa was known as Dark Continent until the 18th century.

1)        The trade of slaves carried on by Europeans brought the European nations in association with the coastal regions of Africa.
2)       To the middle of the 19th century the westerners did not have any idea of the interior of the African Continent.
3)       Africa had dense forests, big lakes, perennial rivers and large tracts of deserts.
However, the composition of Africa was not known to the word at large, hence, it was called the unknown or Dark continent until 18th century