Babylon was a city of the Soumerian civilization build between the rivers of Tigris and Euphrates in a region that is known as Mesopotamia [today's Iraq] and became the capital city of the Babylonian civilization. The famous Hanging Gardens of Babylon one of the seven wonders of the Ancient world were hosted in the city.
Babylon was conquered by Alexander the Great after the battle of Gaugamela at 331 BCE. After his death the conquered territories were divided among his generals and several battles were fought until the settlement.
The inhabitants of Babylon were transferred to Seleucia the capital city of the state of Seleucus at 275 BCE and the city was left deserted. Later under the Parthian Empire the city was populated once more and lasted until 650 AD/ CE.