Ur was an ancient Sumerian city located in Mesopotamia, in what is now modern-day Iraq. It was one of the first cities in the world and is believed to have been founded around 4000 BC. The city was an important center of trade and was known for its impressive architecture, including the famous Ziggurat of Ur, a massive step pyramid that served as a temple, and for its advanced writing system. To this day you can see the remains of the old city of Or.