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