I have been exploring tunnels and hidden, forgotten, or inaccessible places in New York City since 1996. I began taking pictures because I was fascinated by what I found underground in the city, and I wanted a way to capture and convey what I was seeing: labyrinths of utility tunnels, glorious cityscapes from inaccessible rooftops, graffiti murals that only a handful of people would ever see, or century-old underground spaces.