Hiding the longest subterranean river known in the world.

This collection of over 50 murals celebrates Brussels' rich history as the self-proclaimed home of the "comic strip."

This fairytale castle was built as a show of power but was nearly torn down thanks to its history of torture.

Part modern art project, part traditional chapel, this see-through church is only substantial from the right angle.

A journey through 430 years of bulbiculture in the Netherlands.

A lecture hall sink once used by Einstein and other noted physicists is now regarded as a strange science relic.

This towering church is home to a world-famous organ and a treasure trove of medieval art.

A 1:20 scale piece of the Netherlands commissioned by a queen lets visitors take a stroll as giants.

This imposing tower named after the mythical sword of King Arthur is considered the tallest freestanding climbing wall in the world.

Its town washed away centuries ago, this lonely tower by the sea tells the tale of a mermaid and a curse.

A statue of the second-tallest Dutchman in history.

This historical Netherlands fortress still bears the marks of its single siege.

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

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

A grassy pyramid named after a French battle.

The tallest waterfall in the Netherlands is a lovely, stepped feature that is only 50 feet tall.

Drive past the giant fruit sculptures and up to the window for a menu of fruity treats.

The former headquarters of history's oldest megacorporation.

A hidden church in a hidden courtyard tells the story of the Miracle of Amsterdam.

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

It appears as if a man is standing behind this giant airport clock, painting the hands in real time.

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

Incredible labyrinth of man made caves.

This miniature take on the Kremlin is one Dutch man's retirement project.