The remains of a ruined mansion memorialize the 1906 earthquake.

World's oldest operating science fiction and fantasy club, once home to Ray Bradbury and L. Ron Hubbard.

This naturally heated mountainous creek has created a group of neon blue pools of potentially deadly boiling water.

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

A 300-ship graveyard, with a few still visible at low tide.

San Francisco Bay's ghost town.

These millipedes glow not out of attraction, but as a not-too-subtle warning.

This massive redwood tree has a hole in the base big enough to drive through.

Travelers exchange letters with woodland creatures at this mini post office.

The lush coastal city of Astoria is riddled with forgotten secret sidewalks.

This lake in the Cascades lives up to its name, disappearing down a hole every spring.

Nestled in the heart of San Francisco’s bustling Financial District stands a unique homage to the Mayan and Beaux Arts.

A little piece of the Shire is hidden behind a plant nursery in Port Orchard, Washington.

No one knows how this Pacific Northwest spruce tree came to have so many trunks.

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

This Big Sur waterfall drops 80 feet directly into the Pacific Ocean, and inspired the hillside house up top.

A storybook European village in Berkeley.

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

The largest drain hole in the world.

Most famous work of one of Frank Lloyd Wright's sons.

Standing in a state of "arrested decay," this ghost town allows for a detailed peek into Gold Rush life in an unusually harsh climate.

In this century-old literary safehouse, print is alive and well.

A wall of chewing gum moonlights as collective art.

Costumed elves and mountain bikers co-exist peacefully at this abandoned Christmas-themed adventure park.