This ultra-modern California span is actually a titanic solar clock in disguise built by famed architect Santiago Calatrava.

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

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

The fossilized remains of ancient California redwoods.

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

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

Massive prehistoric mammals used these stones as oversized scratching posts.

A monument to the love people have for their pets.

A modest reminder of treacherous waters at the Golden Gate.

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

Concrete strongholds stand guard over the Golden Gate.

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

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

This abandoned boat was left in place thanks to its rotting beauty.

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

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

The last remaining relic of San Francisco's glittering 1915 Panama Pacific Exposition.

27-room home built with the fortune of a sugar magnate.

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 living time capsule of the 1960s Richardson Bay water-front.

Prone to disastrous fires, the city of San Francisco has the Guardian, a fireboat gifted by residents, to watch over them from the bay.

Floating man-made island and upscale restaurant.

San Francisco's newly reopened hands-on science museum.

In all of the 29 years it was in operation, no prisoners ever escaped successfully... or so they claim.