The Ancient Kingdom of Mesopotamia was an ancient civilization located in the region of modern-day Iraq. It was one of the earliest civilizations in the world and is often referred to as the cradle of civilization. The most powerful kingdom in the region was Assyria, which was a major regional power from the 25th century BC until its fall in 612 BC. Assyria was known for its military prowess and its impressive architecture, including the famous Hanging Gardens of Babylon.