This private skyway is filled with art and was expanded explicitly so that Hitler could appreciate a river.

Hundreds of hidden passageways weave through the old quarters of Lyon.

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

Geothermal waterfalls in Tuscany.

These medieval skyscrapers dominate the skyline of this small Tuscan town.

A petite white lighthouse perched on the ancient core of Stromboli Volcano.

A wunderkammer of gold and silver reliquaries and ancient saintly bones.

Birthplace of the "Cat in the Cradle" and a cluster of iconic, original windmills that let the Dutch tame the seas.

This Arabesque Italian castle was built with a primitive, if ingenious, air-conditioning system.

The incorrupt tongue of the patron saint of lost things is venerated in this basilica.

Baroque celebration of the end of the Great Plague of Vienna.

This automated sculpture of two men peeing will spell out text messages with their micturition.

The "dragon babies" of southeastern Europe.

The most visited, and possibly most controversial, museum in Germany.

Walk upon the mementos of the dead in this Parisian courtyard paved with medieval tombstones.

A museum on the history of Paris, including a set of Napoleon's toiletries, Proust's room, and relics of the Revolution.

Notorious artist squat renovated into legal studios.

A Parisian exterminator's shop whose storefront displays stuffed rats hanging from traps.

Religious perseverance and cultural coexistence manifest in an architectural gem that multiple wars couldn't topple.

A musical instrument played by the sea.

Where the lovelorn find a home for their sentimental keepsakes.

Ancient Greek oracle of the dead.

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

This exclusive resort has completely covered a tiny Balkan island in a 5-star warren of guest rooms.