The oldest surviving synagogue in New York City is now a soaring art space.

The abandoned husk of a mental institution that failed to save a Jazz Age icon still sits nearly unchanged.

Read between the lines of the subway map to find the hidden abandoned Civil War fort.

Home to the infamous "Typhoid Mary" and the worst loss of life in New York's history prior to September 11, 2001.

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

This former Norwegian sailor's church is slowly being taken over by ramshackle robot musicians.

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

An abandoned castle owned and ignored by Masons carries a cursed history.

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

Collapsing castle on the Hudson river was once the storage site of military surplus business.

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

A very classy 1920s-era bar right in Grand Central Station.

Read a book next to a Midtown waterfall.

A stunning, two-tiered waterfall made famous by poets, artists and the legend of a ghost dog.

A restaurant on Staten Island showcases a different grandmother’s cooking every night.

Sniff the Titan Arum's rotting flesh.

The one-stop shop for all of your superhero (or evil arch-nemesis) needs.

Just your average Marie Antoinette–themed speakeasy in an abandoned 19th-century subway tunnel.

Under a glass sidewalk lie the remains of some of Manhattan's oldest buildings.

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

A semi-scholarly approach to sex.

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

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

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