Hanging Gardens of Babylon Al-Hillah, Iraq

          The Hanging Gardens of Babylon are said to have been built by Nebuchadnezzar II, a ruler of Babylon, around 600 B.C. Though historians often debate the actual existence of the gardens, because there's no physical evidence and Babylonian documents never mention them (Greek scholars first described the gardens), accounts state that the gardens consisted of vaulted terraces raised above one another and supported on pillars -- in other words, an artificial rising mountain of gardens. The terraces were filled with dirt and planted with trees and flora, which were said to hang over the sides. The amazement over the gardens stems from what would have been an extraordinarily complicated irrigation system, which brought water from the Euphrates to the gardens in an otherwise arid environment. The gardens are thought to have been destroyed by an earthquake around the first century B.C.