An impressive waterfall nestled in the cliffs of Idaho's Snake River Canyon.

The only bridge in the United States where BASE jumping is legal without a permit year-round.

A giant snail sculpture looking longingly at the German traffic museum.

Among the ostentatious rococo ornamentation of this church, an image of death cuts the life-thread.

Housed in an old church, this hunting museum holds a collection of mythical bird-rabbit creatures.

The giant pair of sexy legs sticking out the window of this costume store have become its main draw.

San Franciscans leave gifts and messages for the magical beings that live behind the tiny, mysterious door installed on a tree in Golden Gate Park.

The last remaining relic of San Francisco's glittering 1915 Panama Pacific Exposition.

A walk-in working camera obscura produces 360-degree live images of the San Francisco coast.

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

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

A Barbary Coast watering hole built into a Gold Rush shipwreck.

A modern mechanical planetary system, part of a 10,000 year clock.

A nondescript building that's been functioning as a speakeasy for nearly a century and a half.

A collection of 20th-century automata, penny arcade games, and musical contraptions.

Get lost in this haunting fairytale art walk through a man-made eucalyptus grove.

A tiny theater hidden in an alley plays a constant stream of short silent films for anyone willing to peer through the peephole.

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.

Offering commanding views of the California coastline, this restaurant was a hub for the artists and bohemians of Big Sur.

The Empire Mine is "one of the oldest, largest, deepest, longest and richest gold mines in California."

These whimsical works of art tell the story of the city's past and present.

A more than 260-year-old crypt built on Boston's oldest English burial ground.