For a brief time in 1960s France, families could climb into a tiny submarine and be pulled along an underwater journey.

This "floating railway" is one of the world's oldest monorail systems.

This former steel and coal plant is now a neon-lit industrial fantasia.

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

A dream-like maze full of strange art, surreal spaces, and fantasy landscapes to get lost in.

Visit the ancient, mysterious Roman catacombs ... in the Netherlands.

An open-air sewer system that was covered piece-by-piece over 300 years.

No need to strap in for a "ride" on this walkable roller coaster.

Strange secondhand shop showcasing taxidermy and oddies

A preserved building where the dead were once watched for signs of life.

This functional solar system model was inspired by the famous Eisinga Planetarium.

Houses are tucked between, on, and underneath giant boulders.

An interactive museum dedicated to preserving and sharing the history of the home computer.

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

A former plague hospital turned medical museum.

The place where Czar Peter I of Russia resided in 1697 during his Grand Embassy.

An ancient passage filled with stalls selling used books, once frequented by Vincent Van Gogh.

A floating cat sanctuary on an Amsterdam canal.

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

Repurposed space and ultra-modern construction collide to create this geometric wooden spectacle.

The struggle of a small Dutch island against the sea.

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

Hop aboard a charming bog train to explore this rare open-air museum of peat.

This former hydraulic laboratory is now a woodland dotted with old engineering models.