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

Big gun installations, built over a massive cemetery, now abandoned & hidden in trees.

Guns that have been defending San Francisco since 1904.

There is no trying to fall in love with this Star Wars fountain, you just do or do not.

A huge musical instrument played by the ocean.

At the base of the Golden Gate Bridge, a small sign basically begs for a high-five.

The largest drain hole in the world.

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

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

The fossilized remains of ancient California redwoods.

340 bicycles, 65 feet high.

Nursery with extensive collection of flesh-eating plants operated by the author of "The Savage Garden."

Monumental sculptures of Patrick Amiot, constructed from debris, detritus, and determination.

The mysterious round rocks of Schooner Gulch.

The southernmost outpost of the Russian Empire in colonial America.

Massive prehistoric mammals used these stones as oversized scratching posts.

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

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.

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

The lighthouse central to the 1980s horror classic "The Fog" is, in fact, located in one of the foggiest areas of the Pacific Coast.

An enchanting tunnel of cypress trees leads to an old morse code station still used today.

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

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

Discover for yourself what Herb Caen referred to as "the best kept secret in the Bay Area."