in the northeast, which received large masses of african slaves to work in sugarcane, tobacco and cotton plantations, people of african and mixed-race descent predominate, mostly on the coast, whereas in the semi-arid country land (usually called "sertão") there is a predominance of europeans and amerindian-european mixed people. most of the african or mulatto people in the "sertão" are descended from freed african slaves or mulattos who fled inland from the coast and worked as cowboys for semi-feudal lords. the city of salvador da bahia is considered one of the largest african cities of the world.