This Manhattan skyscraper is a reminder of the brief but glorious age of urban air taxis.

Site of the first pathological and bacteriological research facility in the United States.

The feral felines of Roosevelt Island have a small army of allies and an abandoned hospital all to themselves.

A crumbling hospital from the 1850s on Roosevelt Island.

A sculptural commentary on capitalism pokes up from the East River.

A little lighthouse in New York City, surrounded by mysterious stories of insanity-driven construction.

A former insane asylum despised by Nelly Bly and Charles Dickens is now fashionable apartments.

On this island, you suck away your garbage via an elaborate pneumatic tube system.

This 220-year-old house is a reminder of New York City's Dutch past.

Hidden in one of New York's oldest subway stations is the final remnant of the site of the bizarre Shakespeare Riots.

A terrific purveyor of natural history objects and curios.

The former sign of this immortal music venue is just that--undying.

Phil Mortillaro uses keys to bring art back to the Village.

Manhattan's Thirteenth Avenue was made on landfill then deliberately destroyed — apart from one small, obscure block.

A well-worn marker in a forgotten alleyway is all that remains of what had been one of Manhattan's most beautiful buildings.

This curved Manhattan building was built to house the opulence of John D. Rockefeller's oil empire.

Built hundreds of years ago this downtown iron barrier once protected a much despised king.

This 19th century brick building in Brooklyn stands out like the anachronistic landmark that it is.

The first statue of Christ sleeping on a bench in the United States confused its affluent parish.

A winding district gerrymandered into the shape of a mantis.

Formerly the most gerrymandered district in the U.S., it twisted and turned along racial borders.

This historic building housed the surviving crew members of the Titanic, who were left destitute after the wreck.

A partially hidden wall graffitied by spectators of the 1976 Bicentennial, recently rediscovered.

Down a stairway in the East Village, you could once read a plaque describing an alternate history of a fictional version of Manhattan.