The former home of a mad diplomat is said to still be marked in bloody, arcane scrawls.

Live out your childhood construction fantasies in this one-of-a-kind gyrating hotel.

This fairy tale forest hides scenes from some of the more obscure and bizarre Western nursery stories.

The ruins of this Dutch castle sit atop a labyrinth of once-secret tunnels and passageways, dating back over 900 years.

Incredible labyrinth of man made caves.

A monument hidden in the woods built in 1938 as a getaway for a Dutch museum curator.

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

Birthplace of the "Cat in the Cradle" and a cluster of iconic, original windmills that let the Dutch tame the seas.

The spectacular history of spectacles on display.

A grassy pyramid named after a French battle.

The giant scales in this museum can still tell if someone is one of the devil's brides just by weight.

This beautifully designed star-shaped fort was the premier defense system of the late 1500s.

The Bloemen Route, or “Flower Route”, stretches 25 miles through prime Dutch tulip country as a result of “tulip mania,” the world’s first economic bubble.

Hidden within a Netherlands crater is a stone bed that lets those who lie in it see the sky as a curved surface.

This unattributed sculpture in Amsterdam is hiding in plain sight.

This city square is home to Amsterdam's oldest church and a statue honoring Dutch sex workers.

This impressive collection of rare books on ancient mysticism inspired author Dan Brown.

This basement museum explores the art and artistry of fascism.

Invisible bridge parts the waters, invoking biblical images and preserving the ominous feel of an ancient moat.

Unsurprisingly, Holland is home to one of the most magnificent flower gardens in the world.

Oldest Museum of the Netherlands is a true cabinet of curiosities.

Colorful and chaotic stacked hotel in North Holland.

A floating cat sanctuary on an Amsterdam canal.

A former plague hospital turned medical museum.