The famed amusement district marks the beginning of summer with a wild procession of nautical creatures.

An eerie, existential museum dedicated to the author of "The Metamorphosis."

The hidden lair of an alchemist rediscovered in a 2002 flood.

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

A toy store with a century-long history preserves the craftsmanship of playthings of the past.

A Victorian natural history and ethnographic museum with wonderful turn-of-the-century, science-book-esque evolution displays.

Catacombs turned marketplace.

The only university zoological museum in London houses extinct animals, bizarre natural history specimens, and a Micrarium of microscopic creatures.

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

A Tucson museum and performance space full of found-object movable sculptures.

An Oxford museum where visitors can have tea with the Mad Hatter and climb through the wardrobe to a fantasy land.

Traveling collection of amazing automata.

A tongue-in-cheek arcade where the games are based on everyday life.

Miniature art that tells an enormous story.

A museum of the dime museum that features weird entertainments of yesteryear, from feejee mermaids to flea circuses.

The world's largest key collection features keys to the White House, Frankenstein's castle, and Hitler's bunker.

This Manchester laundromat is hiding something.

This abandoned Slovenian military barracks has become a punky-political art squat.

This Oakland fairytale kingdom, fiercely devoted to childlike whimsy, was an early inspiration for Disneyland.

The walls are decorated with whimsical murals painted by the creator of the Madeline franchise.

Local legends say that fairies used to dance in the moonlight here and invite handsome young men into their grottoes.

A little-known sculpture park of contemporary environmental art in a Lapland forest.

A scattered trail of street art adds a pop of color to the city's stark structures.

Eco-village hidden in the foothills of the Alps that created a massive system of psychedelic underground temples.