The struggle for independence of decolonization caused nation-states to triumph over the empires that had structured much of the world's political life throughout the early twentieth and nineteenth centuries. It mobilized millions of people, sometimes thrusting them into violence and warfare. As permanent features of the world's political landscape, European colonial empires in Asia and Africa appeared in 1900. The age of African independence took place from mid-1950s through mid-1970s as more than fifty colonies emerged into the bright light of freedom.