Urban historian and photographer Steve Duncan climbs down manholes to explore the subterranean world of sewers, tunnels and buried natural streams. In subterranean New York City, a place usually associated with muck and stench, he finds a stunning, otherworldly environment, a reminder that a massive technological edifice sits directly beneath our cities. Duncan returns to the surface with images that reveal the history and complexity of the city, but you can tell it’s the experience he values most. ‘You feel like the last man on earth down there,’ he says, ‘and that’s incredibly rare in New York.’