Hanging Gardens of Babylon

The Hanging Gardens of Babylon were one of the Seven Wonders of the Ancient World, described by Greek and Roman writers as tiers of planted terraces rising above the city of Babylon in Mesopotamia. In the history of roofing they are often cited as the earliest roof garden, although whether they existed, and where, remains uncertain.

The traditional account

Later tradition attributes the gardens to King Nebuchadnezzar II, who reigned from 605 to 562 BCE. The only ancient source to credit Nebuchadnezzar is Berossus, a Babylonian priest writing around 290 BCE. Other classical writers, including Diodorus Siculus and Quintus Curtius Rufus, attribute the gardens to an unnamed "Syrian king".

Descriptions

Diodorus describes brick walls about 6.7 m (22 ft) thick supporting terraces with soil deep enough for large trees. Strabo describes water lifted from the Euphrates by screw devices to irrigate them. Accounts of how the terraces were waterproofed differ between sources.

Doubts

No surviving Babylonian text mentions the gardens. Nebuchadnezzar's long building inscriptions say nothing about them, and no definitive archaeological evidence has been found at Babylon. Scholars have proposed three main explanations:

• the gardens were purely mythical or poetic;
• they existed but were destroyed by around the 1st century CE;
• the story refers to a different garden.

Assyriologist Stephanie Dalley argues that the gardens were built by the Assyrian king Sennacherib (c. 704-681 BCE) at Nineveh, and that the two cities were later confused. Her evidence includes Sennacherib's inscriptions on water engineering, the Jerwan aqueduct, and a relief from his grandson Ashurbanipal's palace showing a mature garden.

Significance for roofing

Whatever their reality, the gardens became a powerful image of plants grown on built structures, and they are routinely referenced in histories of green roofs and roof gardens.