The ancient city of Mesopotamia was Babylon, which was one of the most influential cities in the ancient world. It was located in modern-day Iraq and was the capital of the Neo-Babylonian Empire from 626 to 539 BC. Babylon was renowned for its impressive architecture, including the Hanging Gardens of Babylon, one of the Seven Wonders of the Ancient World. It was also a center of learning and culture, with a library that contained thousands of clay tablets.