The Industrial Revolution created a huge demand for raw materials, such as rubber, ivory, and minerals. Africa was seen as a source of these materials, and European powers began to explore and colonize the continent in order to secure access to them.
Medical advances
Medical advances such as the development of quinine, a drug that can prevent malaria, made it possible for Europeans to explore the interior of Africa without succumbing to disease.
Transportation improvements
Improvements in transportation, such as the development of steamships and railroads, made it easier for Europeans to travel to and within Africa.