The Portuguese sailor Diogo Cao was one of the first seamen that sailed beyond the Canary Islands. Legend had it that behind them would be “the Sea of Darkness”, where gigantic birds and three-faced creatures would haunt you.
In 1482 Cao came to a place where the sea suddenly turned dark, brown-colored. That was where the river Congo ended. It would take until the 19th century before explorers would succeed in sailing up the Congo river, penetrating the “Heart Of Darkness”.