Spanish architects used seized Muslim gravestones to rebuild parts of the fortress.

A museum dedicated to the centuries-old cave dwellings that housed marginalized communities on the outskirts of the former capital of Muslim Spain.

This ancient structure is widely thought to be the oldest intact pyramid in the world.

The video game-themed street art first popped up in the French city.

Stripes of human ashes cover a back lawn in the most sought-after burial grounds in Paris.

A mud statue stands in the dark tunnels, seeming to hold up the weight of the city above.

This bridge was constructed from the rubble of the infamous Bastille.

A Parisian exterminator's shop whose storefront displays stuffed rats hanging from traps.

The tradition of open-air secondhand and antiquarian bookselling in Paris dates back to the Renaissance.

An "inside out" building in the historical center of Paris, featuring Europe’s largest modern art museum.

This massive library holds what was once the largest book collection in the world.

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

A lovely biographical museum in the artist's home of 24 years.

Climb inside an iron crystal magnified 165 billion times its normal size.

Tucked in the back of a flower shop, its collection details the fascinating history of the Netherlands's iconic symbol.

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

This cheese shop also houses a museum devoted to Dutch dairy.

A little sculpture with a large wardrobe.

Cat art as far as the eye can see.

The history and future of cannabis.

This narrow Ghent alleyway is an officially sanctioned street art tunnel.

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

This salt marsh in Southern France is as pink as the flamingos that inhabit it.

This plaza is home to a number of works, including Montpellier‘s own Arc de Triomphe.