The themes of order and chaos are intricately linked to those of sanity and madness. Extended isolation in the wilderness often leads to insanity, a seemingly unavoidable result of chaos. The atmospheric conditions in the heart of Africa—oppressive heat, constant drumming, whispering foliage, and mysterious light—can overwhelm the inexperienced European mind. This environment may either lead one to believe that anything is permissible or, as with Kurtz, drive one to literal madness. After spending years in the jungle, Kurtz is portrayed as a man consumed by insanity due to power and greed. Without any external restraints—neither legal nor moral—Kurtz starts to believe he can do as he pleases, and this perceived freedom drives him mad. During Marlow's journey to find Kurtz, small instances of madness are apparent: a warship firing into the dense forest without reason, the desperately needed rivets that never arrive, bricks that will never be made, a sudden dance, and a massive hole dug without purpose. These events culminate in a row of impaled human heads and Kurtz, who, in his madness, has declared himself a god and conducts ritual human sacrifices. Themes of solitude and silence reach their peak here: they have driven Kurtz insane. He is depicted as merely a voice, a disembodied head, a mouth ready to consume everything. Kurtz speaks of ‘‘my ivory … my intended … my river … my station,’’ as if he owns everything in the Congo. This illustrates the ultimate arrogant madness of the white man, who arrives with the pretense of improving the land but remains to exploit, devastate, and destroy it.