Pythagoras is today best remembered for his way with triangles, but in his time (the sixth century BC) he was quite a polymath – not so much a Renaissance man as a naissance man. His followers regarded him as semi-divine, claiming that he ‘healed the sick with incantations, predicted earthquakes, suppressed thunderstorms, journeyed into the past, and had the capacity to “bilocate”, meaning he could be in two places at once’. On one occasion, Will Hunt writes in Underground, he ‘wrapped himself in a black lamb’s wool and descended into a cave in Crete’, where he stayed for twenty-seven days. When he emerged, ‘pale and haggard’, the philosopher reported ‘that he had experienced death, that he had journeyed to Hades and returned and now possessed sacred knowledge beyond any mortal rhythm’.

In this journey, Pythagoras was imitating Hermes, the messenger of the gods and also the god of boundaries and thresholds, whose task it was to guide the souls of the deceased into Hades. The name Hades translates as ‘the unseen one’, and the word ‘hell’ can be traced to the Proto-Indo-European kel-, meaning ‘conceal’ (think also ‘cellar’). Darkness, concealment and death are the three intertwined concepts that shape our idea of the subterrain, and these themes run through Underground, making it a little surprising that this is such a lively and luminous book. 

The subtitle of Underground is ‘A Human History of the Worlds Beneath Our Feet’. The ‘human’ there really means ‘personal’, as this is a roaming, energetic affair structured around Hunt’s own subterranean adventures. The book delves into natural history and earth science as well as anthropology, myth and urban exploration.