The first cities appeared in southern (1) MESOPOTAMIA. This became the civilization of (2) SUMER. Sumer was a civilization of (3) CITY-STATES, or cities that acted like small independent countries with their own leaders Why did this happen?
As you know, the (4) TIGRIS AND EUPHRATES RIVER PLAIN is a difficult environment. The rivers flooded the land in the spring due to (5) MELTING MOUNTAIN SNOW. The rest of the year it (6) RARELY RAINED and the sun-baked soil was as hard as a rock.
(7) LEVEES were dug along the banks of the rivers to stop flooding. (8) CANALS were dug to shape the path of the water. (9) DAMS were built to force the water where they wanted. This created (10) RESERVOIRS of water.
Building and maintaining an irrigation system is hard work. Canals had to be maintained as they clogged with (11) SILT, or very fine mud. Hundreds of people had to work together. Villages grew to towns and between (12) 3500-3000BC, these towns grew into the world’s first cities. The city-states of Sumer.
As Sumerian city-states grew they fought over the use of (13) WATER. City-states upstream blocked the water from getting downstream. This led to the first civilization bloodshed. By 3000BC the city-states of Sumer had (14) WALLS surrounding their cities as well as (15) MOATS to protect the people from attack.