Professor Iain Stewart continues his epic exploration of how the planet has shaped human history.
This time he explores our complex relationship with water. Visiting spectacular locations in Iceland, the Middle East and India, Iain shows how control over water has been central to human existence.
He takes a precarious flight in a motorised paraglider to experience the cycle of freshwater that we depend on, discovers how villagers in the foothills of the Himalayas have built a living bridge to cope with the monsoon, and visits Egypt to reveal the secret of the pharaohs' success.
Throughout history, success has depended on our ability to adapt to and control constantly shifting sources of water.