When monkeys or other animals multiply, however, they continue to live in troops of roughly the same size. There are no simian cities. We humans are unique in our ability to scale up our permanent settlements. So far as we know, there were no year-round, sedentary communities with even 1,000 residents before Çatalhöyük, around 7000 BCE; none above 10,000 residents before Uruk, Susa, Tell Hamoukar, and Tell Brak in the Near East and Majdanetske, Taljanki, Dobrovodi, and Nebelivka in Ukraine, all roughly around 3500 BCE; none above 100,000 before Nineveh, around 700 BCE; none above one million before Rome, around 50 BCE; and none above 10 million before New York, London, and other early 20th-century supercities.21 Although we have continued to evolve biologically since 7000 BCE, we are still more or less the same animals as we were then. What has evolved out of all recognition is our institutions, giving us the organizational tools for cooperation on much larger scales; and evolutionary anthropologists have consistently concluded that, through most of history, top-down hierarchy has been what made this possible.22
Growth of cities over time