Why did cities first form in Mesopotamia?

No one knows for sure why urbanization began in Mesopotamia. The development of cities could have occurred due to environmental conditions. Lack of rainfall might have been the inspiration for people to organize themselves in a common effort to build cs for the irrigation of farmland. Another reason may have been the need for protection on the open plain, which could have led people to gather together to create walled enclaves. Whatever the reasons, this was the first time in history that humankind channeled its energies towards addressing the needs of a community as a whole.