An eerie, derelict amusement park in Berlin.

A surreal museum of extraordinary industrial objects.

A whimsical and twisted animatronic monster tour beneath the streets of Berlin.

The largest free-standing aquarium in the world resides in a hotel lobby in Berlin.

A complex, nine-layer maze on the grounds of a Venetian doge's playground.

Fall down the rabbit hole into a surreal journey of human consciousness "from ass to soul."

Created by one of England's most prolific labyrinth designers, inspired by Bath city history.

This whimsical castle of grottoes was the labor of love of a French postman, and one of the greatest achievements of outsider architecture.

The fantastic architectural models of a French traveler.

The prototype for all Nazi concentration camps.

A tiled, multi-level garden of survival in Lyon.

Pilgrimage site for star-crossed lovers.

An ancient artistic garden parlor full of hidden water wonders.

The world's largest collection of witchcraft regalia.

The glowing blue Nymphaeum of Emperor Tiberius.

Mother Nature outdoes herself with this stunningly beautiful set of caves carved into marble.

An Italian crevasse filled with abandoned buildings gives visitors a look at the world without humans.

This ancient Irish religious site is covered in ancient carvings, many of which have barely aged.

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

The crypt of the imposing Stephensdom holds royal intestines and thousands of skeletons.

150-year-old satirical tableaus made from stuffed frogs.

A nearly 500-year-old sculpture depicts a man eating a sack of babies, and no one is sure why.

A mythically themed self-built sculpture park.

This memorial commemorating fallen Swiss Guards of the French Revolution has been called the saddest stone in the world.