The Sumerians are recognized by historians as one of the first groups of people to meet all five characteristics of an advanced and complex society. By 3,000 BC, the Sumerians had already built several cities that were surrounded by fields for farming. While these cities shared a common culture, they operated individually in terms of their government. These independent cities are referred to as city-states which are run very similarly to how a country is run today. The Sumerian city-states include Uruk, Kish, Lagash, Umma, and Ur.