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

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

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

New York City's smallest piece of private property.

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

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

Read a book next to a Midtown waterfall.

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

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

Order scoops of pandan, lychee, and black sesame at this family-run institution.

A hip bar decorated with walls of golden skulls.

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

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

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

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

The oldest family-run luncheonette in New York, last renovated in 1948, still serves food and drinks the old-fashioned way.

Try not to get slimed in Tribeca.

Tucked in the back of this amazing antique store is an important piece of medical history.

A terrific purveyor of natural history objects and curios.

A tiny museum housed in a New York freight elevator specializes in the "overlooked, dismissed, or ignored."

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

A crumbling hospital from the 1850s on Roosevelt Island.

An antique curios dealer and hybrid taxidermist.

An all-American grocery store in Paris sells U.S. "cuisine" like Pop-Tarts and Heinz ketchup to homesick ex-pats.