The birthplace of Karl Marx is now a museum dedicated to the communist revolutionary's life and work.

This work of art, which took 35 years to complete, has a motorway running through it.

This medieval castle overlooking the Elzbach river looks just like it did hundreds of years ago.

This Cold War–era fallout shelter was actually a storage facility for the nation's emergency currency.

This 12th-century castle majestically overlooks the city and the beautiful Mosel River valley.

Germany's longest suspension rope bridge.

This 600-year-old home seems to defy physics.

At Monet's beloved home you can still see the Japanese bridge, waterlilies, and weeping willows that were the subjects of some of his most iconic paintings.

The Church of the Annunciation was carved into the face of a cliff, just like the rest of the town of Haute-Isle.

The Devil’s own choice when he needs a drink in Brussels.

This historic stone gate tower is now just a lonely relic in the middle of a swamp.

A coastal French town said to have been visited by Jesus' disciples is a major pilgrimage center for Catholic Romanis.

Built in 1347, this belfry is one of the oldest in the world and survived intense bombing during World War I.

Two ancient yew trees with a chapel and an altar built inside their hollow trunks.

These exceptionally narrow openings between giant rocks will test your daring.

This site used to mark the heart of the EU—now it's crowned with a striking glass sculpture and a buried secret underneath.

Controversially restored in the 1970s, this giant 15th-century mosque is shrouded in legend.

A quaint medieval millhouse hovers surprisingly above the waters of the Seine.

The spectacular and eerie moss-covered grave site of 19th-century Belgian merchant.

A road that ends in the middle of a farmer’s field is one of the only remnants of this once-famous racetrack.

No one knows the story behind the mysterious feline perched on this rooftop.

The 10th-tallest pyramid in the world, this former sports arena is now home to a massive Bass Pro Shops store.

This windmill has been grinding pigments for traditional paints for more than 200 years.

Montmartre's sole surviving windmill became an iconic landmark for 19th-century painters, artists, and bohemians.