Teeming with illegal goods and services, this towering maze of vice is also a popular tourist accommodation.

Walk through spectacular aisles of hanging meat and wagon wheel–sized cheese at the world's largest wholesale food market.

This iconic Parisian bookstore doubles as the "Tumbleweed Hotel" for traveling writers.

A horde of stray cats rule in this secluded Parisian cemetery under a bridge.

This massive library holds what was once the largest book collection in the world.

The abandoned zoo enclosures offer a perfect place to experience the other side of the bars.

High on a hill overlooking Los Angeles lives a world famous, high-power conical Tesla Coil.

Remants of foundations, streets, and streetcar tracks inhabit the cliffs where a landslide occurred in 1929.

World's largest collection of serial killer artwork and other macabre exhibits.

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

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

This iconic L.A. bookshop is housed in an abandoned bank—both symbolic and chic.

Non-profit time travel mart sells goods you would need for a trip through the fourth dimension.

An artsy hidden staircase leads to breathtaking views of San Francisco.

A psychedelic labyrinth on the San Francisco bay.

A huge musical instrument played by the ocean.

A treasure trove of artifacts, books, and artwork from the "golden age" of exploration.

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

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

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.

“Live hard, ride fast, eat pizza” at this joint filled with Evel Knievel memorabilia.

Back in 1952, you could get a mushroom cloud chaser with your atomic cocktail.