As Nottingham’s network of 800 man-made caves inspire an exhibition called ‘Hollow Earth’ at the city’s contemporary art gallery, Shahidha Bari and guests explore the underground world. Archaeologist Chris King discusses discoveries under Nottingham's streets, literary historian Charlotte May suggests stories to read, curator Sam Thorne picks out images, and award-winning cave explorer Andy Eavis, tells us about his career discovering more territory on earth than anyone else alive - all of it underground.

Producer: Ruth Thomson

Hollow Earth: Art, Caves & The Subterranean Imaginary runs at Nottingham Contemporary until January 22nd 2023. Organised in collaboration with Hayward Gallery Touring, the exhibition features works by René Magritte, Santu Mofokeng, Kaari Upson, Jeff Wall and Aubrey Williams, as well as new commissions from Sofia Borges, Emma McCormick-Goodhart, Goshka Macuga, Lydia Ourahmane and Liv Preston. In 2023, the exhibition will tour to The Glucksman in Cork and to RAMM in Exeter.

The Being Human Festival which showcases academic research has several events in Nottingham exploring the city's caves and underground history throughout November 2022. You can find another Free Thinking episode exploring Breakthroughs in electricity research showcased at this year's Festival https://www.bbc.co.uk/programmes/p0dhyp89

The Green Thinking collection on the Free Thinking programme website features a host of discussions about the environment and our landscapes https://www.bbc.co.uk/programmes/p07zg0r2