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

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.

This historic Amsterdam bar used to accept sailor's monkeys as payment.

The attic of a four-century-old canal house hides a clandestine church.

The world's first zoo for microbes collecting the horrible and wonderful things living on and around us.

Cat art as far as the eye can see.

A floating cat sanctuary on an Amsterdam canal.

An Amsterdam street lined with antique shops each one dedicated to a different obscure collection.

This small museum located under the famous cube houses, is home to some 30,000 chess pieces.

This hotel was once home to a steamliner company and became the final rest stop for Europeans heading to the New World.

Old ships and machinery fill a historic harbor in the city that's home to Europe's largest port.

One man's personal kunstkammer, museum and shop.

A collection of 4,000 thimbles that's more versatile than one might imagine.

Horrifically creative torture devices and shame punishments line the walls of this chilling museum.

The history of German architecture is explored across this fairy-scale mini-city.

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.

This German museum is devoted to all aspects of grave culture from headstones to coffins.

The largest treasure hoard in Europe is contained in a castle that was bombed out during World War II.

A unique collection of Swiss art brut and naïve art displayed in an old warehouse.

This museum tells the story of lake dwellers from 4000 BC to 850 BC, replete with stilt houses and goats.

This is not only one of the oldest collections in Europe, but also possibly the most beautiful.

In addition to fine dairy products, the world's most beautiful milk shop also offers a feast for the eyes.

A Black Forest cuckoo clock theme park features one timepiece big enough to walk inside.

This unique Renaissance castle was turned into a home for Nazi occultism.