Part four covers Early American cultures (Tiwanaku, Aztecs, Inca, Mayan, Cahokian, Beni, Majaroan) and the domestication of animals in Europe, which led to major differences between native and European cultures.
Part four covers the earliest arrivals in the Americas, Monte Verde, Clovis, the Holocene Extinction, and the beginnings of agriculture (maize, potatoes, manioc).