"By 1885, when European kings, princes and presidents sat in Berlin to slice up the African continent with their geometrical instruments, the African people had already been devastated by the ravages of the West Atlantic slave trade. In West and Central Africa, the indigenous civilisations lay in ruins, from the sophisticated Saharan trade routes with Timbuktu at their centre, to the empires of Angola. On the Eastern seaboard, the European invasion, led by the Portuguese, defeated and destroyed the city states of Swahili civilisation. All in all, some 40,000,000 souls are estimated to have perished in the triangular slave trade, which lasted for roughly four centuries, 1450–1850. The development of the European and North American industrial revolution and the global lead this gave to Europe and America was in no small measure built on the back of Africans. The colonial episode was thus the tail end of long and destructive contact between Europe and Africa. The slave trade tore apart the very social fabric of African societies, destroying their internal processes of change. It imposed on the continent a European worldview in which the peoples of Africa were at the lowest rung of the so-called civilised order. No other continent, including those that suffered formal European colonisation, had their social, cultural and moral order destroyed on this scale."