Some motifs are decay, darkness, stagnancy, and selfishness. These morbid motifs are repeatedly pounded into the story, so that these ideas are implanted into our brains. These motifs suggest that human nature is responsible for the underlying evil found in us all. Human "darkness" is found in all of us, and Conrad reveals this theme to us by examining the human nature that is revealed in the characters exposed to the twisted African jungle. Everyone respects Kurtz and aspires to be like him, but Kurtz is selfish; he chooses to stay in the threatening jungle to squeeze out as much ivory as he can. The evilness in human nature is blinded from everyone, and when they get caught into this ivory-grubbing frenzy, it'll just be too late. They will be ensnared by the dark, thick jungle.

Definitely the darkness, decay, river, gloomy, death, the sense of being watched, and being locked in could be motifs for this novel.
I think these could be leading to Marlow and the crew will end up finding something gruesome after they reach the end, maybe.

Death and the constant threat of the unknown in the Congo serve as motifs. All that is bad in the human mind, such as fear, manifested in the river. There is no good or joy in the river. Traits that do exist in the Congo are fear, pain, sorrow, and greed, which is the instigator of all the other emotions. Lack of guidance on a hunt to find an elusive Kurtz forces Marlow to make decisions that affect the entire boat and its crew. The only known is the unknown.

-Andy 1st period

Some of the motifs that I've noticed are compassion, selfishness, darkness, confusion, and suppression. It all goes to show that human beings are capable of being virtuous and compassionate but are easily sidetracked towards greed and corruption; it is easier to do bad things than good.

-KatherineC. 1st period