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

Radioactivity still cause for concern at this urban explorer's paradise.

A classically inspired temple in Redwood City.

San Francisco Bay's ghost town.

It took years to decode its mysterious messages.

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

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

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.

The remains of a deserted steamboat sit rusting beside an old ferry pier and an abandoned train platform.

This giant shopping mall still holds signs of its automotive past.

A century and a half of research in the sciences and natural history, still going strong.

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

One man's quest for the ultimate road trip vehicle.

One of the largest trees of its kind in California.

A pair of pure white felines guard the entrance to a spot of California real estate established as an artist's haven.

Housed in a memorial lighthouse, this museum relays the history of surfing, beginning with the antics of royal Hawaiian teenagers.

One of the most elaborate displays of Jellyfish is on display at the aquarium.

The world's first permanently occupied mountain-top observatory continues to report on the stars.

L. Frank Baum wrote part of the "Wizard of Oz" series in this wooden Victorian beach resort.

One of the largest free-standing structures ever built, this dirigible hangar is now simply a giant skeleton.

A sculpture of the famous photograph stands on San Diego's "Greatest Generation Walk."

A burnt orange monolithic dome structure perched on a hillside near Interstate 280.

Home to the "Circus" trees created by Axel Erlandson.