As Heart of Darkness comes to a close, we find Kurtz and Marlow heading back to "civilization" in England from the Congo. Kurtz, already in unstable physical and mental shape, is slowly falling to his death on the boat. When he finally realized he was going to die, Kurtz's last words were "The horror! The horror!" Upon my first time reading this, I was disappointed that these were the only words offered up by Kurtz. The whole book was about meeting Kurtz, and even after we met him, he barely talked. But as I began to think more about his last words, I came to a conclusion that these words hold a lot more meaning.
"The horror" that Kurtz is referring to is all of the things he had done and witnessed throughout his life in the Congo. It pretty much sums up the experience that we have seen through Marlow's eyes. Kurtz's ultimate downfall was a product of his actions throughout his years working for the Company. In the end, it wasn't even worth it because he died and left all his fortune in the Congo, and there was no one left to continue his legacy. Kurtz's reflections on the way he lived his life are basically flashing right before his eyes in this moment and leaves us to think about what "the horror" really means.
I find it interesting that Kurtz's reputations in both Brussels and the Congo are so different. England believes that Kurtz is still a good man, whereas he is infamous in the Congo for being so ruthless.