The Hanging Gardens of Babylon (also known as the Hanging Gardens of Semiramis) and the walls of Babylon were considered one of the Seven Wonders of the World were both supposedly built by Nebuchadnezzar around 600 BC (present Iraq) although there is doubt as to whether or not they had a physical existence.
The Hanging Gardens are extensively documented by Greek historians such as Strabo and Diodorus Siculus, yet little evidence for their existence other than some (circumstantial) evidence gathered at the excavation of the palace at Babylon has been accrued to substantiate what look like fanciful descriptions.