A tube worker being lowered into a tunnelling shaft in Cavendish Square during work on London Underground's new Victoria Line. According to author Will Hunt, there are whole worlds. In his first book, Underground: A Human History of the Worlds Under Our Feet, Hunt takes readers on a journey through the catacombs, Cold War bunkers, subway systems and ancient burrows around the world. For over a decade, he traveled, along with urban explorers and scientists, through subterranean landscapes so few humans dare to tread, in order to discover new insights into human nature. It turns out that the damp, dark spaces miles below our daily life have a lot to tell us about how we think and live.