According to one local tradition, the entrance to the Voodoo underworld can be found in New Orleans through seven gates scattered throughout the city's French Quarter.

A legendary speakeasy bookstore returns from the brink.

This historic "City of the Dead" lies prominently in the center of New Orleans' famous Garden District.

The quaint little store that is said to have inspired a famous Dickens novel was only given its name after the book was released.

Tubing through a cave lit with glowworms is a magical underground experience.

A self-built castle made by a mysterious man.

A Jenga-style cylindrical tower of books that appears to go on forever.

Perfectly preserved ancient monastery in an impossibly dramatic location on a rocky island in the Atlantic.

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

A counter-culture bookstore like no other hides in plain sight in the streets of Paris.

A room in New York City that contains 250 cubic yards of dirt worth a million dollars.

This symbolic piece of New Orleans architecture is also home to a few ghastly stories.

The hidden lair of an alchemist rediscovered in a 2002 flood.

One of the tallest buildings in Iceland, and perhaps, the most visually impressive.

A hands-on traveling collection of the innovative devices of yesteryear.

A museum and shop on Bourbon Street located in the former home of the second Voodoo Queen of New Orleans.

The gorgeous library at Trinity College is home to remarkable treasures of Irish identity.

This New Orleans tree is filled with hidden chimes that produce a carefully tuned melody.

One of Antoni Gaudí's most classic buildings is well-known for its "dragon-back" design.

The world's only international cryptozoology museum is host to an unrivaled collection of mysterious objects.

This fantastical waterfall is hidden in a cave located in a cracked cliff.

Once the most densely populated place in the world, this island is now a ghost town.

A rare view of a preserved Victorian science museum.

Construction of Barcelona's iconic (but controversial) church is expected to be completed in 2026—a century after the death of its architect.