The Seven Wonders of the Ancient World have always captured the imagination of people all over the world. It would not be an exaggeration to say that the Hanging Gardens of Babylon have left many wondering about the mystery of how the gardens were hanging? It is widely believed that hydroponics was the technique used for the construction of these gardens. Hydroponics – the science of growing plants without using soil. This lesson serves as a what is hydroponics all about.