What sort of symbols are there in "Heart of Darkness" that contribute to larger themes in the novel?
There are several symbols that achieve a larger significance beyond the literal meaning of the text. Many of these symbols attach a moral dimension to an image or object. For example, the "darkness" and wildness of the deep jungle also alludes to the depraved state of man's heart. The river journey is a literal journey, but it also symbolizes Marlow's journey into a deeper understanding of Kurtz and his motives. The ever-present fog and swarming flies also possess a significance beyond being simply a distraction during the journey. There are more examples at the link below: