A tour of underground Berlin takes you through WWII air raid shelters and tunnels used to smuggle people out of East Germany.

A whimsical and twisted animatronic monster tour beneath the streets of Berlin.

This surreal statue brings a famous French novel about a supernatural cad to arresting life.

Twelve grave-faced marble angels guard the emperor's tomb at Les Invalides.

In the best of all possible worlds, everyone will get a chance to see this statue in which Voltaire's heart is interred.

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

A majestic lion statue guards this Parisian botanical garden, and feeds on an unsettling item.

A museum on the history of Paris, including a set of Napoleon's toiletries, Proust's room, and relics of the Revolution.

This statue was given to France by the United States to commemorate the centennial of the French Revolution.

A surrealist timepiece by the artist of melting clocks.

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

A scandalous Art Nouveau collaboration that set Paris all atwitter at the turn of the century.

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

A mechanized clock where a man fights off a dragon, crab, and rooster.

This charming cobbled backstreet is the most Instagramable street in Paris, much to the residents' annoyance.

A museum of carnival attractions where you are invited to ride the rides.

A horde of stray cats rule in this secluded Parisian cemetery under a bridge.

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

Notorious artist squat renovated into legal studios.

The macabre collection of Jacques Sirgent, an expert scholar on the undead and all of their trappings.