From the icy poles to the deepest parts of the oceans, humans have explored Earth’s most challenging environments, and have even journeyed on into space. But how did these places form and what are the features that make them unique? How do humans live and work in these harsh landscapes? Most importantly, how is human activity impacting them and their natural inhabitants and wildlife, and what does the future hold for them?

Life at Extremes: Underground explores the wonders that lie hidden beneath our feet, from burrows and caves to the rocky layers that make up the Earth itself. It looks at the unique wildlife that lives below the ground and the rich mineral resources it offers. It also uncovers how humans co-exist with the underground world, using it to build unique hideaways, homes and even whole towns.