After WWI many European powers wanted to acquire new colonies, but most of the territories were already taken, so they turned to Africa.
Britain, France, and Germany were mostly involved. Britain had colonies in South Africa, Rhodesia (Zimbabwe), Egypt and other parts of Africa. France and Germany also had many colonies in Southwest Africa.
To maintain power they used strong military, even the navy and signed the Berlin Conference that regulated the European colonization and trade in Africa. This means the European powers partitioned the continent into parts so they avoided problems back in Europe, but created major problems in Africa, by dividing tribes and cultures.