Colonialism ran rampant for almost 200 years, in some ways still lingering and the racism that exists in our society is a direct consequence of it.
Yeah and the British and the French were already pretty powerful economically at that point and had fought a bunch of wars against each other. This was around the time mercantilism begins and the Europeans wanted to establish "God, Gold and Glory" throughout the world. This literally meant spreading the word of God to "civilize" other people, they would seek out your natural resources for this, usually fukking you over in the deal and would enrich themselves immensely throughout the exchanges. This is where colonialism began.
European cacs truly believed in their eyes and worldview that they were BETTER and more advanced and had to spread their way of life around the world. Mostly, they wanted resources. Whatever it was. Ivory, Furs, Spices, Silks, various metals and the most precious of all, humans. Also many more. They searched the whole world for these things and established their influence where they saw fit. They fought tooth and nail to make this possible. THEY HAD TO (in their eyes). The Kings and Queens of Europe had to have their finest silks and furs, grand pianos and the sweetest tea with their biscuits. All of this expanded rapidly with the development of the Atlantic Slave Trade, which coincided with a time period of highest periods of wealth in human history, all made possible on the backs of slaves throughout various "colonies" in the world.
The ravaging of Africa is the greatest tragedy of human history.