We live on a blue planet, and yet most of us rarely touch that blue. The oceans are remote, inaccessible without ships or scuba gear, but as this gigantic and dynamic reservoir flows around our planet, it has a huge effect on our everyday life. Our weather and climate depend on it, and the battles, trade and food supplies influenced by it have shaped our civilisation. We’ll look at how this engine works, how different cultures relate to it, and what the future holds for the blue of our planet.