The medieval castle built as headquarters for the Pope's secretive Knights Templar.

This gaping hole in the middle of a remote mountain lake looks like a portal to another dimension.

Europe's oldest still-operational tea farm also boasts a spectacular view.

A small but charming botanical garden that contains many exotic plant species.

Building owners can take out tiles for free at this repository for historic building materials.

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

A narrow passage next to a cafe leads to a courtyard exploding with murals, tags, and paste-ups.

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

The small alleys in Lübeck's Old Town are a result of medieval urban sprawl.

This contentious squat has stood through fire, violence, and government intervention as a hotbed of leftist protest.

Once the tallest building in the world, this abandoned church is now a monument to the destruction of WWII.

Hamburgers are intensely proud of their tunnel beneath the river.

A towering monument to war, located on a beautifully peaceful hill.

Cold war icon and onetime "hole" in the iron curtain.

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

Berlin's old airport.

Floating swimming pool within a moored vessel.

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

Berlin's natural history museum houses the world's largest mounted dinosaur and the late beloved polar bear Knut.

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

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

A 12th-century fortress containing some of Berlin's oldest buildings.

An early work of the architect Álvaro Siza Vieira, these swimming pools blend into the beach.

The corpse bride of Portugal.