In the course of human evolution, at a certain point in time, the idea of living in a group with mutual under-standing and sharing became very useful and practical.
From small isolated groups, communities were formed, and then societies, which in due course, became a civilization. But a civilization is much more than just a town; it is an advanced stage of organization.
Civilization roughly means a highly developed social structure enriched by cultural, economic, and creative factors. It can include many things, like how different sections form in the society, how we interact with each other, how we create artistic works, how we dress, or how we govern ourselves.
Most early civilizations flourished on riverbanks. This was because the river made the land fertile, and ensured the supply of water for agriculture.