Order a boozy baba au rhum at the oldest patisserie in Paris.

This abandoned subway station can still be seen on regular commuter trips.

A Manhattan courthouse hides a small but scathing memorial to Holocaust injustice.

Cryptic messages embedded in the New York City sidewalk.

The New York hotel where tragic visionary Nikola Tesla spent his final hours, destitute and alone but for the pigeons.

Cheap pizza and all of your naughty bedroom needs housed in a stunning example of Art Nouveau architecture.

This translucent sculpture represents a quintessential component of New York City's skyline.

A centuries old castle atop a dormant volcano houses museums devoted to both women and witches.

These beautiful garden buildings are among the oldest surviving greenhouses in the United States.

This castle constructed in 1928 was crafted from drawings of Lismore Castle in Ireland.

A Romanesque tower appears when water levels drop.

Of course Salvador Dalí lived in a castle...

Mysterious Spanish catacombs of unknown origins.

Partially collapsed lava tube and cave system complete with concert hall, underground pond, and unique albino crabs.

Village situated on a narrow volcanic escarpment.

Holding the current title of "biggest chair in the world," it stands with little fanfare in Lucena, Spain.

A Spanish town built into the cliffs.

Wonderland replication in progress by one persistent man.

Spanning the El Chorro gorge, this pathway used to be one of the most dangerous crossings in the world.

Three bridges and one giant canyon make up this fantastic Spanish settlement.

A beautiful ruin of a 14th-century Plantagenet castle built by a medieval mercenary.

A huge cathedral single-handedly constructed by one eccentric monk.

At night, bats patrol this magnificent 18th-century space in search of book-eating pests.

A majestic hotel for dreamers rises from the center of a fairytale wood.