Here's your slice...

Through the lectures, I've learned about the Berlin Conference. Basically a German Chancellor by the name Otto von Bismarck invited 14 other Western Countries, including the 4 superpowers of that time (1884-1885) Portugal, British, France and Belgium and none from the African countries to dissect the African regions up to their own preference and colonize them.

Probably the ideal image to sum up the whole scenario.

Now, part of the reasons why they do this was of course to exhibit their colonial power not just to the Africans but to their fellow Western rivals. In simple terms: the more land you own, the more power you have.
Another reason was because of Africa rich resources and raw materials. Even before the discovery of oil, Africa was abundant with diamond, palm oil, cotton and so much more. By monopolizing more of these resources is to be able to control the market.

By taking up the African countries to themselves, it is with no surprise that this comes with serious issue like genocide and slave labor to name a few. Even centuries after the Berlin Conference, Africa is still feeling the effects and repercussions of it. From civil war, countries secede from one another to the entire region heavily dependent on aid and debt.

Here is a video to summarize and illustrate the events after the Berlin Conference, the Scramble for Africa: