This outdoor gallery of graffiti-covered walls pays homage to the past, present, and possible future of street art.

The home of aviation trailblazers, in a remote corner of the big city.

Hidden in plain sight on the Hudson River is an abandoned train station where nature has taken over.

In the middle of downtown Brooklyn lies a 165 year old secret hidden right below the surface (closed to the public indefinitely).

This innocent-looking townhome is actually a subway exit.

A modern zoetrope on the New York City subway.

This sculpture by artist Fritz Keonig survived the 9/11 attacks and now stands as a monument to the victims.

On the Hudson resides one of the largest clocks in the world.

A WWI fighter plane and turn-of-the-century penny candy shop are among the unexpected features of this Financial District building.

Once the tallest building in the world and the site of "the highest dinner ever held in New York" this building now holds the most expensive penthouse in the city.

A beautiful and abandoned New York subway station from 1904, complete with chandelier.

Try not to get slimed in Tribeca.

Play heads or tails with thousands of different coins.

The crown jewel of the Queens Museum is a nearly 10,000-square-foot architectural model of the city originally built for the 1964 World's Fair.

Plot your trip through the city on the sidewalk.

New York City's smallest piece of private property.

This exemplar of modernist architecture is meant to captivate and inspire students of the Cooper Union.

This abandoned subway station can still be seen on regular commuter trips.

The name of this famed hospital was once a byword for the horrors of medical and psychiatric care.

A three-story copper skybridge connects two Manhattan buildings with Art Deco luxury.

Nondescript elevator doors open to reveal a stunning, surreal world.

The last remnants of what was once one of the world's grandest hotels can now be found in a Manhattan subway station.

There must be a pun in this haystack somewhere...

An unassuming secret door once led to a legendary watering hole.