A hip bar decorated with walls of golden skulls.

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

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

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

Elevated freight railway turned wildly successful urban park.

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

Manhattan’s Battery Park has a whimsical carousel full of spinning, glowing fish.

This abandoned subway station beneath the Waldorf-Astoria hotel is allegedly used to secretly transport presidents.

Try not to get slimed in Tribeca.

Dodge prohibitionists and slide through the telephone booth in Crif Dogs.

This beautiful building in the heart of Manhattan's Financial District was empty for decades.

The world’s oldest and biggest bookstore stocking only mystery, crime fiction, espionage, and thrillers.

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

A crumbling hospital from the 1850s on Roosevelt Island.

La Monte Young and Marian Zazeela's "Dream House" will immerse you in an ever changing world of sound and light.

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

An abandoned Roman salami factory has found new life as an art space home to 200 squatters.

Also known as the Square Colosseum, this building is a prime example of fascist-era rationalist architecture.

2300-year-old Roman road connecting the empire.

A hidden workshop for creating and restoring Papal mosaic masterpieces.

If you want to talk to the Pope you will have to stare down this surreal vision of Jesus rising from a nuclear hell.

This subterranean shrine beneath a bike rental store celebrates the iconic Italian scooter.

This statue is the only female representation of Rome's "talking statues."

This ancient market is often referred to as the oldest shopping mall in the world.