Final answer:
Around 750 BC, villages began uniting to form cities, with Uruk in ancient Mesopotamia being a notable example. These cities arose due to the benefits of intensive agriculture and subsequent surplus, which led to increased population density, division of labor, and the centralization of power.
Step-by-step explanation:
Around 750 BC, the phenomenon of villages uniting to form larger cities was a critical development in human civilization. This pattern of urbanization can be seen in the history of ancient Mesopotamia. By the late fourth millennium BCE, the city of Uruk emerged as a prominent example, expanding into a walled city harboring tens of thousands of inhabitants.
The birth of these urban centers was largely fueled by the advantages of intensive agriculture, particularly in fertile areas such as the valley of the Tigris and Euphrates rivers. These agricultural practices produced a food surplus that supported larger populations and allowed for a division of labor, sparking the rise of craft specialization, regional trade, monumental architecture, and the centralization of power.
Similarly, in locations outside of Mesopotamia such as Peru and Mesoamerica, cities like Caral and Monte Albán were established. Well-planned cities supported by agricultural surplus laid the foundations for political and social complexity. The first settlements that qualified as cities, including the Sumerian city of Eridu, evidenced a blending of cultures and a switch from a nomadic to a settled way of life. These early urban agglomerations eventually gave rise to some of the world's first imperial capitals like Agade, Ur, Babylon, and Nineveh, which shaped the course of human history.