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

Half of a house.

Golden Gate Park's historic collection of plants.

Handmade treasures from around the world.

Spiral labyrinth hidden in the hills above Oakland, CA.

A house built from trash known as the poor man's Hearst Castle.

The location of the last stand of Charles Manson's doomsday cult.

Not merely a museum – but a whirring powerhouse that offers a subterranean peek into the heart and soul of cable car operations.

The hidden jewel of Disneyland: a members only playground for the Disney elite.

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

Inside an old airplane hangar, friends and strangers alike play on a massive trampoline.

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

An overlooked and unassuming engineering marvel.

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

Bonsai garden in Oakland is curated by the first non-Japanese female bonsai master in the United States.

A world-class observatory in the California desert.

The unbelievably opulent home built for an infamous newspaperman.

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

San Diego's most historic and haunted home.

Hundreds of trees made from glass bottles make up this forest on Route 66.

The programmatic glory of LA's giant whiskey barrel building has become an upscale reminder of the city's kitschy roadside past.

The lowest point in North America is home to an undrinkable pool surrounded by fields of geometric salt flats.

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

Magical-looking cottages that inspired one of the most famous animated films ever.