Gold Rush-era tombstones line the park's paths.

A popular tourist cave with a dark past.

A monument to the love people have for their pets.

The restored and active Victorian-era final resting place of San Francisco.

Life in this isolated, hilltop lighthouse was lonely, but it sure was lovely.

Golden Gate Park's historic collection of plants.

A ruined hotel with an unlucky history and an eerie present.

The most unique castle in all of Southern California, entirely constructed from repurposed materials.

San Franciscans leave gifts and messages for the magical beings that live behind the tiny, mysterious door installed on a tree in Golden Gate Park.

The now-abandoned tunnels were built for the transcontinental railroad on the route where the first wagon train entered California.

Secret Manor, a house full of legends, the least of which is the haunting of long-deceased ladies of pleasure.

An overlooked and unassuming engineering marvel.

Located on 420 acres in the high desert, this spiritual center is dedicated to the "science of the future."

Commonly referred to as the most photographed Victorian home in the United States.

The L.A. Zoo has a secret garden of rare bootleg cycads, a palm specimen dating back 280 million years.

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

Rodin's famous depiction of Dante's 'Inferno', amidst a sculpture garden of many of his other works.

A historic hotel that made a cameo in Hitchcock's classic film has no intention of letting guests forget its fame.

This shop and studio is dedicated to the art of the book, from letterpress to bookbinding.

This concrete tangle of square pipes has stood as a proud thorn in the city's side since the '70s.

San Francisco's oldest surviving monument and meeting place for 1906 survivors.

This unlicensed collection of fast-food memorabilia sits on the site of the first ever McDonald's restaurant.

An extraordinarily ornate museum in San Diego holds wondrous anthropological treasures.

The randomness of this wall of lava lamps helps encrypt up to 10 percent of the internet.