“In the mediaeval imagination, this was a region of uttermost dread… where the heavens fling down liquid sheets of flame and the waters boil… where serpent rocks and ogre islands lie in wait for the mariner, where the giant hand of Satan reaches up from the fathomless depths to seize him, where he will turn black in face and body as a mark of God’s vengeance for the insolence of his prying into this forbidden mystery. And even if he should be able to survive all these ghastly perils and sail on through, he would then arrive in the Sea of Obscurity and be lost forever in the vapours and slime at the edge of the world.”

Peter Forbath, The River Congo : The Discovery, Exploration And Exploitation Of The World’s Most Dramatic River (1977)