Probably the most famous New York City urban legend concerns the (giant) (blind) (maneating) (albino) alligators that (reputedly) lurk in the New York City sewer system. According to reports, the alligators feed off the rodents, reptiles and vermin that breed in the city's ripe pipes, with an occasional drifter as an appetizer.
Back in the earlier 20th Century, pet alligators became a fad. According to the legend, City kids bought baby alligators as pets and flushed them into the sewer system when they grew just big enough to be dangerous. The creatures then bred, or so it's said. Although everybody always knows someone who did the flushing, actual first-person reports are scarcer than hen's teeth.
However --- there have been sporadic newspaper accounts of sightings throughout the years, including the most famous one, published in the February 10, 1935, edition of The New York Times, about an 8-foot-long gator that was pulled from a Harlem manhole. There have been authenticated reports of snakes finding their way up through toilet piping. And researchers have found that conditions in the sewer system are damp enough, dank enough, dark enough, warm enough and humid enough to support an alligator colony. So --- ???