Question

Africa was known as dark continent until the 18th century

Answer 1

The most common answer to the question, “Why was Africa called theDark Continent?” is that Europe did not know much about Africa until the 19th century, but that answer is misleading. ... They called Africa the Dark Continent, because of the mysteries and the savagery they expected to find in the “Interior”

Answer 2

Africa was known as dark continent until 18th century because the europeans and other dominating nations didn't had an idea about it due to its vast desert, dense forests, etc...
Hope this helps you...