This 11th-century castle sits so low you can't see it behind the surrounding buildings.

A 'living museum' in Leiden, the oldest of its kind in the Netherlands.

The world's first interactive human body museum also serves as a chair for a giant orange man.

In the Netherlands, one of the world's largest private car collections can be found.

A seven-century-old jail tells a not-so-pleasant history of crime and punishment.

Rumored to have been frequented by Vincent van Gogh, it's the only remaining genever producer in the Hague.

Now a museum, this building was once a 14th-century monastery and the place where the founder of the Dutch nation lived and was assassinated.

This monument pays homage to a classic Dutch tune.

Unchanged for centuries, this medieval library keeps its books in chains.

Once the local rulers had gone these enchanting ruins housed common folk in an almost real life fairy tale.

This noble mash-up in eastern Luxembourg is part Medieval, part Renaissance, all castle.

This tri-part waterfall is a little bit of fairytale beauty in the heart of Luxembourg's Little Switzerland.

An expansive complex of subterranean tunnels is all that remains of one of Europe's most formidable medieval fortresses.

Two standing giants remain as a tribute to Luxembourg's metallurgical past.

Hiding the longest subterranean river known in the world.

An early 20th-century sanatorium, long abandoned and now being reclaimed by nature.

Descend into the tunnels to experience the life of a coal miner.

This sprawling Belgian fort was once thought of as impenetrable but now it is simply an abandoned relic.

This abandoned Belgian fortress is purposefully being left to nature.

This giant urban staircase was built to keep the city's brave fighting men from getting waylaid in the red light district.

The bridges portrayed on EU currency aren't fictional anymore.

A miniature city, once ruled by the Queen of the Netherlands.