Mist is a recurrent motif in Heart of Darkness, and it is central to our understanding of Marlow's view on the thematic light/dark conflict of the novel. Mist or haziness immediately implies ambiguity, and is used in this capacity by Conrad to distance himself from any absolute conclusions that Marlow reaches. Moreover, the mist that lies over London in the opening scene is dark and brooding, whereas the mist Marlow encounters on the Congo is blindingly white (which has its own racial connotations), adding to the parallels between Europe and Africa that serve to juxtapose them thematically throughout the novel. Kurtz himself is also described, in Marlow's first encounter with him, as a pale vapour, suggesting his ambiguity through a connection to the obscuring fogs and vapours the reader has already encountered. It suggests, furthermore, that Kurtz lives within the same kind of hazy unenlightened state as most other characters in the novel, despite his purported insight and zion status. This is the fog that clears in Kurtz's final realisation and exclamation: The horror, the horror!