A beautifully eclectic mix of architectural styles.

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

This gorgeous reading room houses the oldest and largest art history library in the Netherlands.

This 22-floor tower's Skydeck offers panoramic views of Amsterdam.

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

A curious collection dedicated to human and animal anatomy and pathology.

Museum preserving torture methods from the past.

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

The world's only museum devoted to the wonders of fluorescence.

These Bullet-scarred bunkers are haunting reminders of the Spanish Civil War.

A hidden medieval crypt where a famous legend says the devil used to teach black magic.

This amazing example of Valencian Art Nouveau looks more like a cathedral than a public market.

This ancient tunnel is one of the most important examples of Roman hydraulic engineering in Spain.

A well-restored ancient archaeology site gives a real feel for life during the Roman age.

Abandoned tunnels dug for the once-thriving sea salt industry on the coast of southern Spain.

A daily pyrotechnic celebration marks a beloved tradition during Valencia's festival season.

This huge abandoned fortress hidden inside a mountain holds a world of subterranean secrets.

The deserted remains of a luxury hotel turned hospital ward.

An abandoned tuberculosis hospital said to be haunted by the patients who died within its walls.

Building owners can take out tiles for free at this repository for historic building materials.

Hidden beneath a beautiful overlook you’ll find the history of the city depicted in comic strip format next to a pay toilet.

This once-forgotten oasis in the middle of Lisbon was first created over a century ago quite by accident.

This oddly shaped church resembles a rocket.

A windswept necropolis carved into the rocks overlooks the "most Portuguese town in Portugal."