A local dialect born in the late 19th century is only spoken in this isolated California valley.

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

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

Abortion, prohibition, religion, war, and fear all play a part in the history of this idiosyncratic Pacifica castle.

A large instrument played by the wind.

The old Niles Canyon Aqueduct in the San Francisco Bay Area is a bemusing and secret trail through nature for wayward travelers.

Outside San Francisco lies a small clown cemetery and memorial.

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

The southernmost outpost of the Russian Empire in colonial America.

This partially buried wreck is one of the most complete of its kind but is only revealed when the sea allows.

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

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

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

The seawater playground of gilded-era San Francisco burned to the ground in 1966.

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

The remains of a ruined mansion memorialize the 1906 earthquake.

Big gun installations, built over a massive cemetery, now abandoned & hidden in trees.

Barely visible foundations remain where Stow Lake’s “observatory” once welcomed visitors.

A 300-ship graveyard, with a few still visible at low tide.

The remains of a 12th-century chapter house in Golden Gate Park.

A monumental cross hides in the trees in Golden Gate Park.

A garden oasis filled with flowers mentioned in the works of William Shakespeare.

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

Over 315,000 preserved amphibians and reptiles in jars.