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

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

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

A playing field for a popular French past time can be found tucked away in a quiet corner of Golden Gate Park.

The remains of a ruined mansion memorialize the 1906 earthquake.

A historic hotel that made a cameo in Hitchcock's classic film has no intention of letting guests forget its fame.

This private residence was the template for one of the most beloved television homes of all time.

The rustic cabin-like decor of this Arts and Crafts-style church reflects the love of nature central to its little-known theology.

A tiny theater hidden in an alley plays a constant stream of short silent films for anyone willing to peer through the peephole.

This shop and studio is dedicated to the art of the book, from letterpress to bookbinding.

A library and museum dedicated to typography.

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

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

The southernmost outpost of the Russian Empire in colonial America.

A poignant memorial to a young boy whose death spurred a dramatic increase in organ donations in Italy—dubbed the "Nicholas Effect."

340 bicycles, 65 feet high.

The unedited photograph called "Bliss" has graced the screens of over a billion computers.

Internationally-recognized arts center housed in a century-old former military barracks.

A working model of the entire San Francisco Bay and much of the Sacramento River Delta, complete with regular tides that change every 14 minutes.

Centuries of biking history are nestled in the shadow of the birthplace of contemporary mountain biking.