The world's largest reflecting pool is just two centimeters deep.

The prototype for all Nazi concentration camps.

A fake medieval village in the middle of Turin.

A chapel on a volcanic core, marking the end of a successful journey.

A Gothic cathedral created from volcanic rocks.

A copy of the famous statue can be found in this Florence piazza, along with one of the most breathtaking views of the city below.

This bronze boar's snout has been rubbed to a golden sheen by visitors seeking good fortune.

Pompeii's less famous neighbor is still revealing her secrets.

Erotic art covers the walls of the largest ancient pleasure palace.

The walls and streets of the ancient city are peppered with penises.

The only remaining collection of flayed figures made by French "madman" Honoré Fragonard.

This Parisian gem is one of the most incredible ethnographic museums in the world.

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

France's most famous cemetery, with some of its most curious tombs.

The bizarre visions of H.R. Giger, tucked away in a Swiss medieval city.

A hidden church in a hidden courtyard tells the story of the Miracle of Amsterdam.

This city square is home to Amsterdam's oldest church and a statue honoring Dutch sex workers.

The attic of a four-century-old canal house hides a clandestine church.

Established in 1638 to battle the Black Death, Hortus Botanicus Amsterdam is a treasure trove of rare flora.

The world's first zoo for microbes collecting the horrible and wonderful things living on and around us.

This unreal Portuguese palace looks as though it's made from a pile of different castles.

Elaborately carved to showcase the glorious wealth that the age of exploration brought to the Portuguese empire.

A king's pet, a pope's gift, an artist's inspiration, and a tragic shipwreck.

One man's exploration of the human form, including the bizarre and delightful "Man Attacked by Babies."