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

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

San Francisco's newly reopened hands-on science museum.

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

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

Its buzzing collection honors vibrator history.

A winding path built in secret on the edge of the continent.

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.

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

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

This steamer is known as "The ship that built Cleveland."

This Czar-funded, onion-domed, lavishly muraled Orthodox Church played a starring role in "The Deer Hunter."