A pair of slides and a tree-lined stair corridor have been an urban oasis for nearly 40 years.

Tiki luxury on Nob Hill.

Staircase winds down the side of Telegraph Hill through gardens, wild parrots flying overhead.

The one-time watch house for incoming ships at the Golden Gate now stands abandoned and hidden in trees.

A shop full of natural curiosities, carnivorous plants, and costumed taxidermied mice.

Relics of the 1894 Midwinter Exposition continue to delight visitors today.

Carnivorous plants, medieval aphrodisiacs, and the largest original wood structure glass conservatory in the western hemisphere.

There is no trying to fall in love with this Star Wars fountain, you just do or do not.

A psychedelic labyrinth on the San Francisco bay.

In all of the 29 years it was in operation, no prisoners ever escaped successfully... or so they claim.

Bring your own cardboard to the slippery slopes of concrete hidden in a neighborhood park.

An artsy hidden staircase leads to breathtaking views of San Francisco.

A huge musical instrument played by the ocean.

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

Skeletons, medical artifacts, and other obscure and precious treasures all displayed in a wooden pharmacist's cabinet.

Collection of antique taxidermy and natural specimens, near one of Paris's oldest flea markets.

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.

Inside a former cabaret, seven floors of erotic art.

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

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

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

A surrealist timepiece by the artist of melting clocks.

Dolls of all shapes and sizes display the eras of femininity in this spooky and beautiful collection.