A beautifully eclectic mix of architectural styles.

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

The history and future of cannabis.

Established in 1638 to battle the Black Death, Hortus Botanicus Amsterdam is a treasure trove of rare flora.

A floating cat sanctuary on an Amsterdam canal.

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 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.

A 16th-century fountain marks the site of a lost medieval cemetery once filled with mass graves.

Notorious artist squat renovated into legal studios.

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

This former “ante-chamber to the guillotine” has been refurbished to illustrate the brutal history of French justice.

The very center of Paris is surrounded by a bevy of strange good luck rituals.

A counter-culture bookstore like no other hides in plain sight in the streets of Paris.

A series of abstract, silly sculptures represent the works of a great modern classical composer.

Walk upon the mementos of the dead in this Parisian courtyard paved with medieval tombstones.

The bar where "The Great Train Robbery" was planned was once a nexus of high society and low morals.

London's last remaining public soapbox site has seen speeches from Karl Marx, Vladmir Lenin, and George Orwell.

Claiming to be the oldest hat store in the world, this historic haberdashery had a hand (and a head) in the creation of the Bowler.