The Mole People

One of the most disturbing books I have read is The Mole People: Life in the Tunnels Beneath New York City by Jennifer Toth. Urban legends about homeless people living in the tunnels under New York were trumped by this sociological essay written by a reporter while she was interning at the Los Angeles Times. The stories it contains - which some claim cannot be authenticated- go beyond roasting rats and rarely venturing above-ground:

Many tunnel people are solitary loonies not unlike the guys you see living aboveground in cardboard boxes in any large American city. In a few cases, though--this is where it gets truly weird--sizable communities have coalesced, some allegedly numbering 200 people or more, complete with "mayors," elaborate social structures, even electricity. Toth describes one enclave deep under Grand Central with showers using hot water from a leaky steam pipe, cooking and laundry facilities, and an exercise room. The community has a teacher, a nurse, and scampering children.

Toth traveled in the tunnels and interviewed some of the inhabitants, which she estimated to number 5,000. Her tale, even if it is embellished, is creepy.