An elaborate gift from Claus Spreckels is now a piece of San Francisco history.

A masterpiece in Golden Gate Park by virtue of the artist’s debt.

The only visible piece of San Francisco's most famous shipwreck.

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

Gold Rush ship-turned-hotel buried underneath San Francisco's financial district.

Early prototype for Frank Lloyd Wright's Guggenheim.

A famous alternative culture epicenter and where Joplin serenaded young hippies.

Longtime headquarters of controversial boys' club for the world's wealthiest and most powerful.

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

Not merely a museum – but a whirring powerhouse that offers a subterranean peek into the heart and soul of cable car operations.

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

A favorite haunt of dinosaur loving children and hallucinogen loving hippies alike.

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

San Francisco's oldest surviving monument and meeting place for 1906 survivors.

The oldest burial ground in the city, final resting place of city founders, Ohlone natives and murderers alike.

A tribute to the life and work of the beloved "Peanuts" cartoonist.

A veteran Disney animator turned his gift for storytelling to a museum devoted to his love of a California city.

This historic California cemetery holds the bodies of veterans of both the Civil War and the Donner Party.

California's own majestic geyser is powered by a subterranean volcano.

This surreptitious shop is only open five hours per week.

This grinning pup statue is all that's left of what was once a ubiquitous Bay Area diner chain.

This print shop boasts one of the largest pinball arcades in San Francisco.

The sole surviving relic of the San Francisco neighborhood cobbled together from old horsecars and streetcars.