The Hanging Gardens of Babylon were considered to be one of the Seven Wonders of the Ancient World, and the only one of the Wonders that may have been purely legendary. They were purportedly built in the ancient city-state of Babylon, near present-day Al Hillah, Babil province, in Iraq. The Hanging Gardens were not the only World Wonder in Babylon; the city walls and obelisk attributed to Queen Semiramis were also featured in ancient lists of Wonders.[1]

The gardens were attributed to the Neo-Babylonian king Nebuchadnezzar II, who ruled between 605 and 562 BC. He is reported to have constructed the gardens to please his homesick wife, Amytis of Media, who longed for the plants of her homeland.[2] The gardens were said to have been destroyed by several earthquakes after the 2nd century BC.[citation needed]

The Hanging Gardens of Babylon are documented by ancient Greek and Romans writers, including Strabo, Diodorus Siculus, and Quintus Curtius Rufus. However, no cuneiform texts describing the Hanging Gardens are extant, and no definitive archaeological evidence concerning their whereabouts have been found.[3][4]

Ancient writers describe the possible use of something similar to an Archimedes screw as a process of irrigating the terraced gardens.[5] Estimates based on descriptions of the gardens in ancient sources say the Hanging Gardens would have required a minimum amount of 8,200 gallons of water per day.[6] Nebuchadnezzar II is also reported to have used massive slabs of stone, a technique not otherwise attested in Babylon, to prevent the water from eroding the ground.[citation needed]