Below is a list of the most noteworthy symbols found throughout Heart of Darkness, as well as their meanings and implications in the novel.
- Congo River - Marlow's journey on the Congo River can be said to represent a journey into one's inner spirit. As Marlow progresses further up the river in his search for Kurtz, he begins to learn more and more about himself. He comes to realize that he probably has more in common with the natives than the smug Europeans who have come to civilize them. At the end of his journey, Marlow learns that everyone has a dark side to them, but that some people can conceal it better than others.
- ivory - The ivory symbolizes greed and the destructive nature of man. The managers and agents of the Company are so obsessed with obtaining ivory that they forget about their morals and so-called civilized ways.
- white worsted - Marlow discovers the white worsted wrapped around a negro's neck at the Outer Station. The fabric can be said to represent the attempt of the Europeans to colonize the natives, and the strangling effect it has on them.
- Kurtz's painting - The painting at the Central Station is perhaps the most extensive symbol in the novel. The painting is of a blindfolded woman carrying a lighted torch, which distorts her face. The woman likely symbolizes the Europeans who have come to civilize the natives. The torch she carries represents the European customs and values that they try to force upon the native Africans. The woman is blindfolded because the Europeans cannot "see" the negative effects that their customs have on the natives. Her face has become distorted because, to the natives, the European customs seem rather repulsive.
- Eldorado Exploring Expedition - This group is symbolic of the Whites' search for something that cannot be attained. Eldorado is historically known as a city of gold that never actually existed. However, the prosperity that could possibly be gained was so overwhelming for this group that they felt compelled to risk their lives for it.
- candle on the steamship - Marlow brings a candle into Kurtz's quarters as Kurtz is dying on the ship. The candle is symbolic of Kurtz's losing struggle for life. When Kurtz finally submits to death, Marlow blows out the candle.
- General Manager - The manager symbolizes all the immorality of European colonization. It is no coincidence that he ran the most disorganized and deplorable station in the region. The manager led his station not through intelligence and acumen, but rather, through his ability to stay healthy and invoke uneasiness. He was not interested in actually colonizing the region. His only concern was to attain as much ivory as possible.
- Kurtz - Kurtz represents man's dark side and what can happen when it envelops you completely. Kurtz's prolonged exposure to the untamed regions of the Congo has removed all his ties to civilization. He no longer feels satisfied with just being a mere mortal, so instead transforms himself into an omnipotent being. Kurtz's descent into madness is firmly established with his disturbing final words, "The horror! The horror!"