The world's only known button museum.

This unauthorized stone mermaid was secretly carved out of public stone before being permanently preserved.

A lush green oasis in the middle of Chicago.

A Bibliophile's Dream.

A giant bronze coil of feces is both a tribute to doggie defecation and a reminder to pick it up.

This morbid, delightful curiosity shop offers everything from animal bones to human teeth.

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

This off-beat, quirky communism-themed bar isn't afraid to poke fun at its history.

Museum dedicated to the terror regimes of Hungary.

Built in 1870 at the bridge that connected Buda and Pest, this spectacular incline railway was almost lost forever during World War II.

This Budapest bar allows drinkers to leave their mark on the walls, floor, and even ceiling.

An off-the-beaten-path boutique stuffed with an eclectic collection of upcycled goods.

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

How did a French journalist’s grave become the sexiest statue in the cemetery?

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

The first green space constructed on an elevated viaduct.

This Parisian café sticks almost exclusively to an ethos of reuse.

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

Down a cobblestone alleyway is a museum dedicated to Romanticism, with a secret garden.

Stroll through retro Paris while shopping for old postcards and discarded doll heads.

A Parisian cemetery where the elite and artistic are interred beneath an eccentric collection of tombs.

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

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

The vast, legendary catacombs hold secrets much stranger than stacked bones.