!Around 3500 B.C., the Neolithic villages in some regions developed into cities. These were the first urban civilizations: in Mesopotamia and in Egypt, India, and China The first civilizations are also known as fluvial civilisations. Egypt on the banks of the Nile, c,china and India next to the Yellow River These large rivers rose at certain times of the year. The flooded land was fertilised by the sediments in the water (silt) and when the water level decreased, large harvests were obtained. In order to control flooding, hydraulic works were constructed, such as canals (artificial channels) and dikes (walls to contain the water Thanks to these improvements, the quantity and variety of crops increased, trade and craftsmanship grew, economic prosperity spread and the population increased.