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

The history and future of cannabis.

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

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

A floating cat sanctuary on an Amsterdam canal.

Cat art as far as the eye can see.

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.

Dummies recreate radiological discoveries from history.

Theme park featuring miniature replicas of European monuments.

This collection of over 50 murals celebrates Brussels' rich history as the self-proclaimed home of the "comic strip."

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

This demon atop the Notre-Dame de Paris looks utterly bored.

Exquisite wall sculptures carved in secret by an early quarryman in an obscure corner of the Paris Catacombs.

A unrivaled and rather horrifying collection of wax dermatological models.

The largest medical and anatomical collection in France lies hidden from the public.

A subterranean shelter remains intact under a busy Paris railway station.

The history of radiation is on safe display at the foot of a radiation science laboratory.

Paris' fabled purveyor of exotic taxidermy and natural history curios.

Statue of death tucked in the University of Medicine courtyard.

This museum houses an imposing skeleton army comprised of creatures great and small.

Behind the pink curtain, Au Bonheur du Jour, an art gallery of erotic archives.

A surrealist timepiece by the artist of melting clocks.