The Sumerian people were very smart and they seemed to be able to become the world's first great civilization even with a lack of natural resources. For example, they did not have access to wood, or stone. What they did have access to, was mud, and lots of it, in thanks to the Tigris and Euphrates Rivers.
To continue, the Sumerians were a very unique group of people. They arranged their civilization into city-states, which was a form of political organization. These city-states were ruled by kings, who were warriors who proved their leadership in battle, because of all the fighting that took place. For the most part, kings and priests controlled all of Sumer, while slaves worked on it. City-states were the first organized places where a civilization developed, as most of the other people of the world were still nomadic. The Sumerians were polytheistic, which means they believed that more than one god existed. These people were very much into religion, and they created massive towers called ziggurats to pray and offer different sacrifices to prevent bad things from happening to them. A common practice among .
the Sumerians was something called Animism, which is the belief that a divine force or god lives within natural objects, such as rivers or mountains. Their belief that the earth was created through a series of punishments influenced later civilizations that formed in the Middle East. (SOURCE).
This civilization continued to thrive for almost two decades, but decline was inevitable. The Sumerian people simply could not withstand invaders and began to fall to outside parties. The first of the invasions began in 2400 BC when an Akkadian king conquered the city-states. Their first ruler was Sargon I, who controlled almost the entire region by himself. The Sumerian culture and economy still lived on in this new empire, but the way of life that was once known, was gone. This was the beginning of the end for the Sumerian people and Sumer, and by 2000 BC, they almost completely ceased to exist.