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

Built just after the American Revolution, the oldest row house in New York City still stands in Chinatown.

The first museum in the United States dedicated entirely to posters.

This speakeasy continues the Prohibition-era legacy of Harlem's jazzy Swing Street.

Walking around West Harlem reveals a scavenger hunt of beautiful bird murals.

In the back of a nondescript sports bar is a museum-worthy mural by legendary cartoonists.

This small New York museum celebrates the mountainous artwork of a Russian mystic.

Cheap pizza and all of your naughty bedroom needs housed in a stunning example of Art Nouveau architecture.

Beautiful mosaics cover the first stations opened on New York City's newest subway line.

This wall on a street corner in Lower Manhattan has been a blank canvas for a rotation of renowned artists since the 1980s.

Cryptic messages embedded in the New York City sidewalk.

Nikola Tesla's former home contains an homage hidden from plain sight.

An artist's cute bronze subway sculptures belie his violent artistic past.

For over 30 years the walls of this Harlem schoolyard have been a gallery of street art by "Kings and better."

A masterpiece of LGBT art has been restored in what may now be the most valuable restroom in America.

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

A tunnel once abandoned now thrives with graffiti art as an off-limits makeshift gallery.

A room in New York City that contains 250 cubic yards of dirt worth a million dollars.

Hidden in Central Park's Ramble is a troublesome cave buried just beneath the surface.

A hands-on traveling collection of the innovative devices of yesteryear.

A hip bar decorated with walls of golden skulls.

A New York garbage depot holds a secret collection of weird and wonderful refuse.

A Pythagorean funhouse that tries, successfully, to prove that math is the coolest thing ever.

This lower Manhattan bar is set up in an old bank vault that rests beneath a skyscraper that hides even more historic splendor.