A powerful book, this, and beautifully written. Author Robert Macfarlane explores the caverns, crypts, mines, tombs, glacial caves, underground nuclear waste storage facilities (!), subterranean rivers, and forest root systems beneath our unknowing feet. He meets able guides in all these realms, people who know their way through the caves or mines or catacombs. And he ponders how human technology can change the world. The striking book cover painting represents a holloway – a road so well traveled that it’s worn way down into the ground. Specifically, it’s looking through a holloway toward a nuclear blast.