Civilization describes a complex way of life that came about as people began to develop networks of urban settlements. The earliest civilizations developed between 4000 and 3000 B.C.E., when the rise of agriculture and trade allowed people to have surplus food and economic stability.

While modern civilizations extend to every continent except Antarctica, most scholars place the earliest cradles of civilizations—in other words, where civilizations first emerged—in modern-day Iraq, Egypt, India, China, Peru and Mexico, beginning between approximately 4000 and 3000 B.C.

Scholars generally acknowledge six cradles of civilization. Mesopotamia, Ancient Egypt, Ancient India, and Ancient China are believed to be the earliest in the Old World, while the Caral-Supe civilization of coastal Peru and the Olmec civilization of Mexico are believed to be the earliest in the New World.

Modern humans evolved in Africa around 300,000 years ago and initially lived as hunter-gatherers. They migrated out of Africa during the Last Glacial Period (Ice Age) and had populated most of the Earth by the time the Ice Age ended 12,000 years ago.

Early homo sapiens or modern humans appeared in Africa around 20,000 years ago. After thousands of years, these homo sapiens laid the foundation for the early forms of human civilizations with the development of agriculture, weaponry, art, social structure, and politics.