Ancient civilizations first developed along major rivers like the Tigris and Euphrates rivers in Mesopotamia over 5,500 years ago. They invented writing to help manage production, land, and taxes. Major early civilizations included Mesopotamia, where the Code of Hammurabi established a set of laws, and cities first appeared with structures like ziggurats. Greek civilization began around 3,000 years ago and was centered around prosperous city-states like Athens and Sparta. The Greeks were interested in philosophy, science and art, and invented democracy as a new form of government. The Roman Empire expanded from the city of Rome and dominated the Mediterranean world for centuries, building cities, monuments