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

A tiny museum housed in a New York freight elevator specializes in the "overlooked, dismissed, or ignored."

A psychedelic labyrinth on the San Francisco bay.

An exquisite tunnel of cascading flowers.

A mysterious "wedding cake" castle in the middle of the urban desert.

The artist James Turrell is repurposing an extinct volcano crater as an observatory to experience the cosmos.

An arsenic-filled pool in the Grand Canyon takes on the appearance of a giant, overflowing pumpkin.

A reproduction of earth's many biomes.

This secluded aqua waterfall in the Grand Canyon is the perfect swimming hole, and the Havasupai tribe's fiercely protected natural wonder.

A self-built castle made by a mysterious man.

An abandoned facility that has become a place of ritualistic satanic worship, or so rumor has it.

A peculiar mansion built by the troubled heir to the Winchester Rifle Company fortune.

La Monte Young and Marian Zazeela's "Dream House" will immerse you in an ever changing world of sound and light.

A terrific purveyor of natural history objects and curios.

A huge musical instrument played by the ocean.

A beautiful and abandoned New York subway station from 1904, complete with chandelier.

A hidden architectural treasure in New York's Brooklyn.

One Brooklyn man's collection of life-size fiberglass statues has taken over his entire yard.

A no-frills cinephile haven known for showing offbeat, underseen films.

A working metal shop and venue for outrageous art and music shows in a former cannonball factory.

I fought the law and the precinct caved in.

A curious friendship between two inanimate ladies.

A charming "tea atelier" hidden away in Greenpoint, Brooklyn.

The most complete statue of this Aztec god sits a top a throne carved with images of hallucinogenic plants.