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

Forgotten and then destroyed by fire, this was once one of the largest saltwater swimming pools in the world.

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

Radioactivity still cause for concern at this urban explorer's paradise.

A classically inspired temple in Redwood City.

A 1920s speakeasy that had rum runners racing up and down the shores of California.

The graffiti-covered remnants of a former triangulation station are balanced precariously on this California peak.

A vast city of the dead, where the deceased outnumber the living by more than a million.

The final resting place of the Emperor of the United States and Protector of Mexico.

The peaceful gravesite of a rugged wild west gunman echoes the touching story of his last days.

A burnt orange monolithic dome structure perched on a hillside near Interstate 280.

A rough granite monument marks the spot where Europeans first caught sight of the San Francisco Bay.

A large instrument played by the wind.

Another of California's unused Cold War missile defense complexes has become a graffiti gallery.

This controversial depiction of the "Founder of California" looks as though it was sculpted from mashed potatoes.