They were once known as one of the Seven Wonders of the World — a manufactured mountain towering above the Babylonian plains, build by King Nebuchadnezzar II for his favourite wife, who was homesick for trees and mountains on the featureless Mesopotamian landscape, in what is now Iraq.

The Hanging Gardens were terraced roof gardens, built over a massive arching stone foundation and huge storage rooms.

The roofs were waterproofed with layers of bitumen, reeds, bricks and lead, and enough soil was added to suit trees. Deep wells supplied water to the gardens by means of a hydraulic machine.

Herbs would have been a popular ingredient in the famous gardens, as Babylonian records of the day show that the citizens had thyme, coriander, saffron, anise, poppy, mandrake, rosemary and hemp, as well as ornamentals such as roses, lupins and anemones.

There were probably many more exotic plants in the gardens as Iraq was on the classic Silk Road between East and West. In the millenia before Christ, the Arabs took full advantage of their location between the spice-producing eastern countries and the spice-consuming Western countries, to establish a virtual monopoly on trade.

However, in about 40ad, the secret of the wind systems over the Indian Oceans was unlocked by a Greek merchant named Hippalis. He observed that twice a year the prevailing winds — the monsoons — changed direction.

The Romans soon took advantage of this to establish a regular sea route to the East from Egypt, virtually killing the overland route in the process.