The site of a concentration camp where inmates were made to take part in one of the largest counterfeiting operations in history is now hauntingly empty.

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

The Bauhaus-style former industrial complex is considered the world's most beautiful coal mine.

Twisted buildings adorn the banks of the Rhine river.

A castle from the Holy Roman Empire that hosts traveling youth... in its stables.

This Berlin island is home to a flock of free-roaming peacocks, as well as a historic ivory folly.

An industrial relic is now one of Europe's most staggering art spaces.

This incredible stone temple is a monument to death, victory, and fantasy architecture.

The "Prussian Versailles" that is as glorious today as when it was built.

This historic stone bridge has an entire neighborhood clinging to its sides.

Explore the complex ecology of this multifaceted nature preserve by riverboat.

This "floating railway" is one of the world's oldest monorail systems.

Started as a kitchen garden, now the second largest botanical garden in the world.

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

A sprawling Baroque park with 300-year-old hydro-pneumatic waterworks.

The largest bell in the world has been swinging high above a Cologne cathedral for almost a century.

Granting the right of way to ships over surface traffic since 1917.

This Cold War siren is one off the last of its kind still standing with its immensely powerful original horn.

A museum dedicated to the history and exploration of both popular music and science fiction.

A huge musical sculpture and other art installations on the National Oceanic and Atmospheric Administration grounds.

Seattle's own bad art museum located inside Cafe Racer.

A vista of the city and sea from atop the little-known viewing deck on an unassuming Columbus statue.

Gaudí's famously flamboyant architectural style is on full display in this sprawling park and garden.

Mountain where Jesus was first tempted by the Devil.