Two major dividing lines have formed the megastructure of Eurasia, determining the historical epochs of the continent's peoples. The first, vertical (longitudinal) line has separated East and West since the Paleolithic Age. The East was dominated by Mongol peoples speaking Sino -Tibetan, Manchu-Tungus, and Altaic languages. The Caucasoid peoples of the West spoke mostly Indo-European, Semite, and Finno-Ugric languages. The second line divided the continent horizontally (by latitude) into North and South. This division was closely connected with the Eurasian Steppe Belt. To the north of it lay...