In Joseph Conrad's "Heart of Darkness," the character Marlow reflects on the darker aspects of human civilization and history. He acknowledges that many places which are now considered civilized were once shadowy and enigmatic regions, full of brutality and moral ambiguity. This observation highlights a recurring theme in the novel, where the line between civilization and savagery is blurred.

Marlow's statement serves as a reminder that the past is filled with darkness and that the progression toward enlightenment is often complex and fraught with challenges. The exploration of these "dark places" reveals the potential for both destruction and revelation in the human experience, compelling readers to confront the duality of mankind's nature.