Sumeria, the first civilization in history, arose in Mesopotamia, the region between the Tigris and Euphrates Rivers in modern-day Iraq. Made up of approximately a dozen city-states that often warred with each other, the Sumerians developed a civilization that, backing out modern technology, was in many ways not very different from the one we have today. They built the first true cities and had a highly sophisticated society in the 4th millennium BC. Making important innovations in agriculture, architecture, astronomy, law, literacy, mathematics, and more, their contributions lived on in other cultures after the fall of their own in 1750 BC. Following are some of their more important developments.