A collision of human error and natural geothermal pressure created this rainbow-colored geologic wonder.

This historic estate on the east shore of Lake Tahoe was home to an eccentric millionaire (and his pet elephant, Mingo).

The largest drain hole in the world.

A huge collection of rocks, gems, and crystals.

This corn maze so big you may want to pack a lunch, and possibly a flaregun.

An old-timey medicine shop that once served Chinese laborers during the Gold Rush is still open for business to this day.

Eclectic collection of dark and macabre antiques.

The beauty and the beast of hydraulic mining is on full display at this California Historic State Park.

Dentist's hated concrete colossi are now beloved icons of the community.

The first U.S. town to secede from the Union, only to vote themselves right back in.

This 19th century train workshop is a treasure trove of railroad history.

A working miniature city designed to teach kids about safety and presumably city planning.

Frank Lloyd Wright died a year before construction on his largest public project even began.

Discover for yourself what Herb Caen referred to as "the best kept secret in the Bay Area."

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

This 19th-century church is now a popular roller rink.

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

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

A museum befitting the city responsible for supplying the majority of the world's LSD.

A tiny theater hidden in an alley plays a constant stream of short silent films for anyone willing to peer through the peephole.

This (occupied) house is 10 feet wide and full of spite.

A 140-year-old castle with underground caves hidden in San Francisco.

A large instrument played by the wind.

The graffiti-covered remnants of a former triangulation station are balanced precariously on this California peak.