Once the home of a hermetic monk, this cave now houses a small church.

The largest crypt ever constructed in France was built in the 11th century on an ancient Druid sacred site.

The famous winding walk at Chartres is surrounded in mystery and myth.

A remarkable cabinet of curiosities in an art space in the center of Berlin.

A monument to the three wars that led to German unification towers within a Berlin traffic circle.

One of downtown Berlin's last reminders of its Communist past.

Blitzkrieg bop your way through Berlin's Ramones Museum.

Where once there was a train station bathroom, there is now this German burger joint.

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

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

This futuristic German spa allows visitors to float in a pool of salt water while zoning out to underwater techno.

Lake within a lake.

A patch of contaminated land reclaimed as a scrappy sculptural oasis.

This mesmerizing kinetic sculpture blossoms endlessly in the breeze.

A swirling spectrum of stained glass dazzles visitors who enter this subway station.

This crumbling industrial fortress has attracted daredevils, filmmakers, and historians.

One of the most easily accessible examples of the rare 1960s UFO houses.

This beautiful 19th-century temple stands atop the ruins of its predecessor.

The fairy tale castle of the "fairy-tale king."

The "Little Ones," show Portugal in full miniature splendor.

Hidden beneath a beautiful overlook you’ll find the history of the city depicted in comic strip format next to a pay toilet.

A unique seaside cave where Aleister Crowley faked his own death.

An ancient and majestic fortress that played an integral role in Portugal's road to independence.

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