The Hanging Gardens of Babylon was one of the Seven Wonders of the Ancient World. Fed by the waters of the Euphrates River, the gardens hung over a 130 meters square terrace about 25 meters off the ground. Additional terraces and rooftop gardens on the ziggurats contributed to the gardens. In 1934, a member of the Adventure Society found a reference to the Hanging Gardens of Babylon at the Royal Library of Alexandria.