An abandoned, unfinished mansion on grounds strewn with lava rocks.

Concrete strongholds stand guard over the Golden Gate.

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.

A B&B on a Victorian lighthouse station in San Francisco Bay.

This infamous prison has a store where you can buy goods crafted by incarcerated people.

Astronomers plan to launch a space telescope into orbit, to find out what exactly stands in the way of an asteroid hitting Earth.

Wheels of chrome by the thousands adorn this California Historical Landmark.

Of all the origin stories for weed's secret code, this one likely has the goods.

Law-protected wreckage serves as a peculiar memorial for an almost forgotten World War II tragedy.

One man's love of natural beauty led to the creation of this hidden granite monument.

Frank Lloyd Wright died a year before construction on his largest public project even began.

This whimsical seashell-shaped place of worship was designed to blend into its surroundings.

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

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

California's own medieval Italian castle, authentic down to the 300-year-old iron maiden in the dungeon.

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

The haunting ruins of Jack London's dream house.

The fossilized remains of ancient California redwoods.

'Cause the fence start shaking, the earth was quaking.

This collection of hand fans doubles as a history of femininity.

A huge work of Burning Man-inspired outsider art on the grounds of a California winery.

340 bicycles, 65 feet high.

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

Built by the inventor of the radio, this abandoned hotel has housed early radio employees, military men, and a dangerous cult.