Charting secret rivers below cities with explorer and photographer Steve Duncan

Self-titled “urban-historian and photographer” Steve Duncan has a powerful fascination with all things subterranean – particularly in cities. “I try to peel back the layers of a city to see what’s underneath,” he says. “From the tops of bridges to the depths of sewer tunnels, these explorations of the urban environment help me puzzle together the interconnected, multi-dimensional history and complexity of the world’s great cities.” Realising that beneath each city lies networks of tunnels, sewers, passages and river diversions, he decided to use his photography skills and sense of adventure and try to capture it to reveal to the rest of us above ground, with fascinating results. His photographs are now used in National Geographic, and prints of his work are available on his site.