A tree-like building perches on its trunk in the Steglitz neighborhood of Berlin.

The bunker where Hitler took his own life is hidden under this deliberately ordinary parking lot.

On the Spree bank, discover one of the last reminders of a symbolic wall that divided, and was torn down by the people.

An abandoned NSA listening post on Berlin's "Devil's Mountain."

Art and a pun, all in one.

Thousands of coffin-like pillars make up this controversial Holocaust memorial.

A surreal museum of extraordinary industrial objects.

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

A tour of underground Berlin takes you through WWII air raid shelters and tunnels used to smuggle people out of East Germany.

Europe's only museum solely dedicated to the history of whaling still has a fully-functioning whaling ship.

Mound of stones marking the burial site of the world's most famous orca.

The former home of Norway's greatest romantic composer.

A naturally occurring tunnel in this Nordic mountain makes it look like it's been shot.

Norway's oldest cathedral still in use.

One of the most breathtaking railways in Europe also takes one of the steepest climbs, from fjord to mountain plateau.

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

The world's largest solar furnace uses 10,000 mirrors to concentrate the sun's rays to generate power.

This French castle is said to have once held the Holy Grail but is now a gorgeous mountaintop ruin.

French commune at the heart of conspiracies.

Small French town or alien garage?

Historic medieval fortified city in southwest France.

The experimental test tracks of a retro-futuristic monorail still stand in the French countryside.

This castle-fortress is a living example of the transition from medieval defenses to modern fortifications.

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