San Francisco Bay's ghost town.

One of the last free public hot springs is decorated with hippie art.

The unbelievably opulent home built for an infamous newspaperman.

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

One of the ghostly stops along Route 66.

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 oldest burial ground in the city, final resting place of city founders, Ohlone natives and murderers alike.

The site of murders and Satanic cult gatherings.

The ghost town that ended up on Ebay.

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

This ultra-modern home clings to the slope of the Hollywood Hills on a precarious stilt.

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

The largest drain hole in the world.

Abandoned bridge hidden deep in the San Gabriel Mountains.

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

In a city filled with Frank Gehry buildings, one stands out as one of the architect's weirder works.

Finale of "William Tell Overture" can be heard as drivers pass over grooves in the road.

An unfortunate geological resemblance to Satan has labeled this Pasadena gorge as a passage to the underworld.

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

The largest permanent Monopoly board makes one of the longest games even bigger.

This abandoned Navy base was transformed into an off-grid alternative living community for thousands of people.

Experience a quartz crystal sound bath inside a storied, all-wood sound-chamber.

A Swedenborgian glass church surrounded by redwoods sits perched atop a massive landslide area.

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