In Eurasia and North Africa, civilizations existed with writing, centralized governments, cities, the use of metals, the use of domesticated animals, and agriculture to produce surplus food. Nothing comparable existed on other continents. It emerged slowly and only partially in the Americas and sub-Saharan Africa over the next five millennia. And it never emerged spontaneously and indigenously in Australia. Scholar Jared Diamond identifies the causes, not specifically in the aptitudes or genes of the populations, but rather in the geographic and climatic characteristics of the territory and the opportunities it offered.
