Farming And Irrigation
Farming was accidentally discovered when someone stored seeds underground for the winter. Later on, the seeds grew into plants. They grew, because the seeds were stored near the Tigris and Euphrates rivers. This is all it took to begin farming in civilizations. Eventually, the Tigris and Euphrates rivers weren't enough, so they built canals and ditches to keep the land irrigated in even more areas. Basically speaking, farming is the building block to all civilization, and it allows it to grow in other aspects.