The Power of Water

Matt Baker and Sammi Kinghorn are in Bannau Brycheiniog National Park, where the power of the water that runs through its valleys shapes the landscape both above and below ground. Matt joins a local caving team who are protecting the UK's deepest cave system, while Sammi visits a 200-year-old mill still driven by the force of the water.

From one of the wettest corners of the UK to one of the driest, Adam Henson is in Lincolnshire, where a farmer is taking a gamble on a classic Mediterranean crop that thrives in dry conditions: olives.