The story of humanity begins in prehistory, a vast era stretching from the emergence of Homo sapiens around 300,000 years ago to the invention of writing around 3,200 BCE. During this period, humans developed tools, language, art, and social structures without leaving written records. A turning point came with the Neolithic Revolution around 10,000 BCE, when nomadic hunter-gatherers in the Fertile Crescent (modern Iraq, Syria, and Turkey) transitioned to settled agriculture. Crops like wheat and barley were among the first domesticated plants, and the domestication of animals provided reliable food, labor, and transportation while also introducing zoonotic diseases that would later shape human populations across civilizations.
The world's first civilization emerged in Sumer, in southern Mesopotamia, around 4,500 BCE. The Sumerians developed cuneiform writing around 3,200 BCE, a breakthrough that enabled record-keeping, codified laws, literature, and the transmission of knowledge, marking the traditional boundary between prehistory and history. Nearby, Egyptian civilization flourished with the construction of the pyramids, especially the Great Pyramid of Giza around 2,560 BCE, monumental tombs that demonstrated advanced engineering, centralized state power, and religious beliefs about the afterlife. Narmer, also called Menes, unified Upper and Lower Egypt around 3,100 BCE, founding the First Dynasty and creating one of history's longest-lasting civilizations. To the north, the Babylonian king Hammurabi (r. 1792–1750 BCE) created one of the earliest written legal codes, famous for its standardized punishments and the principle of "an eye for an eye."
These early civilizations flourished during the Bronze Age (~3,300–1,200 BCE), an era when bronze tools and weapons transformed warfare and daily life across Mesopotamia, Egypt, the Indus Valley, and China. However, this era ended dramatically with the Bronze Age Collapse around 1,200 BCE, when the Hittites, Mycenaeans, and Egyptian New Kingdom all fell in a relatively short span. Causes likely included invasions by the mysterious "Sea Peoples," prolonged drought, earthquakes, and the collapse of long-distance trade networks. This widespread upheaval created a power vacuum that would set the stage for the classical civilizations of the next millennium.