A psychedelic labyrinth on the San Francisco bay.

A 140-year-old castle with underground caves hidden in San Francisco.

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

San Francisco's most expensive hotel suite includes a secret passageway rumored to have been used by JFK.

This tall and trim architectural oddity is one of the skinniest buildings in San Francisco.

A library and museum dedicated to typography.

These six walrus head statues harken back to a time when this area wasn't far from the oceanfront.

The first fresco Diego Rivera painted in the United States can be found in the former San Francisco Stock Exchange.

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

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

Noble beasts perhaps, but not the Emperor's dogs.

A pair of mutilated bronze octopuses slump at the base of the monument honoring California's admission to the U.S.

A former hardware store near Yerba Buena is the official home of California's history.

An art supply shop holds the secrets of this quiet neighborhood's raucous Barbary Coast past.

A library built during San Francisco's pioneer times is a student's retreat, bibliophile's sanctuary, and chess player's delight.

A shining, cold, black organ lies in San Francisco's financial district.

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

Faceless white figures loom over the city from the rooftop.

With the touch of a button, you can read a randomly selected short story.

This museum explores the history of the book, from scrolls to mass-produced objects through tools, stories, and massive cast-iron binding machinery (some of it operational).

A collection of memorabilia from the Beat era in the back of a San Francisco bookstore.

The second building of its name to occupy this location might be the finest flatiron building in San Francisco.

Early prototype for Frank Lloyd Wright's Guggenheim.

This teeny-tiny park built by a San Francisco man in 1962 is mostly stairs.