Pierfrancesco Cenni flicks a switch on a portable fluorescent lantern, turns a knob to increase its intensity, and heads into the dark. “Use your phones’ flashlights, and put your feet where I put mine,” he calls out as he descends into the cool, damp underground air. At the bottom of a narrow flight of concrete stairs, with another flick, he turns on a massive fluorescent lamp, revealing a vast, two-story chamber, where thick cement pillars shoot up from bare earth into the darkness and girders hold up the ceiling. We’re…
