How did Joseph Conrad’s Heart of Darkness portray the Congo River region?

In Joseph Conrad’s novella Heart of Darkness, the Congo River region is portrayed as a site of profound moral and psychological decay, serving as a backdrop for the horrors of Western colonialism.21

Conrad depicts the river as a conduit for imperialistic exploitation, where the pursuit of ivory and power leads to extreme violence and the dehumanization of the Congolese people. The narrative uses the journey up the river to symbolize a descent into both a geographical "heart of darkness" and the "darkened psychic interior" of Western civilization. The atmosphere is characterized by:23

• Foreboding and Evil: The story conjures a sense of treachery, greed, and nihilism, famously culminating in the character Kurtz’s dying realization of "The horror! The horror!".41
• Psychological Impact: The isolation of the jungle environment forces the protagonist, Marlow, to confront human depravity and his own emotional kinship with those he initially expected to despise.42
• Critique and Controversy: While the work critiques the brutality of the Congo Free State, it has faced significant postcolonial criticism—notably from Chinua Achebe—for dehumanizing African people and using them merely as a backdrop to explore the white psyche.2