Babylon was a key kingdom in ancient Mesopotamia. The city was built on the Euphrates river and divided in equal parts along its left and right banks, with steep embankments to contain the river's seasonal floods. Babylon was originally a small Akkadian city dating from the period of the Akkadian Empire c. 2300 BC.The town became an independent city-state with the rise of the First Amorite Babylonian Dynasty in the nineteenth century BC. After the Amorite king Hammurabi created a short-lived empire in the 18th century BC, southern Mesopotamia became known as Babylonia and Babylon eclipsed Nippur as its holy city. The empire waned under Hammurabi's son Samsu-iluna and Babylon spent long periods under Assyrian, Kassite and Elamite domination. After being destroyed and then rebuilt by the Assyrians, Babylon became the capital of the Neo-Babylonian Empire from 609 to 539 BC. The Hanging Gardens of Babylon was one of the Seven Wonders of the Ancient World. After the fall of the Neo-Babylonian Empire, the city came under the rule of the Achaemenid, Seleucid, Parthian, Roman, and Sassanid empires.