In the era of colonization, the general ideals of the colonizing European countries were that "other" places (Africa, Central America, etc.) were either currently unfit for "civilized" life and therefore needed teaching to join their progressive world, or their ignorance must be exploited, giving Europe hassle free slave labor that the rest of the world was ignorant of or blinded by. Belgium in the Congo was no different but slightly unique. This government was oblivious to the torture because of the front that they were "civilizing" the "savages". This was where the rift formed between two worlds: the progressive and the underdeveloped. Marlo's and the narrator gives us an image for this division: the Thames vs the Congo. The Thames is the perfect example of expansion. Filled with merchant ships traveling between worlds with new goods and cultures, and surrounded by expanding buildings and business. And then there's the Congo. Jungle lining the banks, filled only with the native "savages", no growing skyscrapers or churches, government buildings or hospitals. To Belgium, and the rest of Europe, this means something needs to change. The people of the Congo cannot be left alone. They must either be immersed or exploited.