New York Underground

[Sandhogs]
Photograph by Bob Sacha

Seventy stories below daylight “sandhogs” install air ducts in a new artery for New York City’s water. City Tunnel No. 3 will add 60 miles (97 kilometers) to a multilayered subterranean network that slakes the city’s thirst, transports its people, and channels its light, heat, and voices.