A living archive of urban activism and space reclaimed.

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

Unlock the secrets of the conjuring arts.

This ruined fort hidden at the top of Central Park can't seem to keep from losing its historical plaques.

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

The world's oldest hologram gallery and the labyrinthine laser laboratory of a holography pioneer.

A historic 1890s architectural masterpiece with an iconic clock tower that, once open to the public, now faces an uncertain future.

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

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

Hidden in an ordinary Midtown building is a one-room museum dedicated to the greatest escape artist.

A celebration of capitalism in Midtown.

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.

The oldest surviving bridge in New York City, which reopened to pedestrians in 2015.

This little museum is built on a theater that was once a wildly elaborate speakeasy.

A dilapidated dock tells the story of Titanic's missed arrival.

Amid the bustle and noise of the Financial District hides a secluded garden oasis above the city streets.

Become a prohibition rebel.

A semi-scholarly approach to sex.

Whisper secrets in a busy station only to be heard on the other side of this acoustic arch.

Read a book next to a Midtown waterfall.

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

A miniature rainforest is growing inside of a Midtown Manhattan office building.

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