Op-art architecture designed for happiness.

The topiary maze at the Habsburg hunting lodge.

A small museum filled with over 1,000 clocks, and one particular clock calibrated to run until the year 9999.

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

The house that took a plunge into the facade of a museum.

Venice's "Island of the Mad."

100 year tradition of fist fights, marked by marble footsteps.

This Venice bookstore has resigned itself to constant flooding by keeping its books in bathtubs and boats.

Renaissance hospital featuring a rotating door into which unwanted babies were dropped.

The oldest operating pharmacy in the world features 800-year-old recipes.

A large grotto built in the 16th century amidst Florence's famous Boboli gardens.

A French library that makes sure its love of books is writ large... giant in fact.

An ancient Egyptian temple in the middle of Madrid, Spain.

Commonly acknowledged as the only public monument to the Devil himself.

This eccentrically decorated palace is replete with grottoes, fountains, tunnels, and caves.

Legacy of the earthquake that nearly wiped Lisbon off the face of the Earth.

A garden in Lisbon filled with giant porcelain creatures.

Natural history museum celebrating biodiversity with a parade of taxidermy animals.

Remains of Roman amphitheater hidden in a sleepy quarter of Paris.

19th century pendulum and a clock restored by a rogue group of guerilla artists.

A grotto-like lodge decorated with gilded mosaics, rocks and a noisy waterfall was the setting for the most sumptuous pleasure house of 1900s Europe.

A museum which takes visitors to the côté obscure of Paris.

A museum of magic with a Sadist past.

Behind the pink curtain, Au Bonheur du Jour, an art gallery of erotic archives.