Underground Britain

North Of England (1x3)

Air date: Nov 06, 2014

In this episode, Rob explores two natural wonders in the Yorkshire Dales - a mile of caves and one of Britain's deepest potholes. In Stockport, Rob learns how its unique geology made it the perfect spot to build the country's largest air-raid shelter and he discovers the incredible depths that are being plumbed to retrieve agricultural fertiliser.