The legendary building that needed ghostly approval before being built.

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

This iconic L.A. bookshop is housed in an abandoned bank—both symbolic and chic.

Bring your own cardboard to the slippery slopes of concrete hidden in a neighborhood park.

A psychedelic labyrinth on the San Francisco bay.

World's largest collection of serial killer artwork and other macabre exhibits.

An artsy hidden staircase leads to breathtaking views of San Francisco.

A peculiar mansion built by the troubled heir to the Winchester Rifle Company fortune.

During prohibition, corrupt city officials ran drinking dens under the streets of Downtown Los Angeles.

A huge musical instrument played by the ocean.

A replica of the first public theater built in California.

Where the first "expert riders, willing to risk death daily" for the Pony Express were recruited.

Pillars made of 700 pieces of luggage climb to the ceiling of Sacramento Airport's baggage claim.

A mesmerizing disco ball-like sculpture along the Sacramento River Walk.

Puzzling...this tree looks like an assemblage of dismembered monkey limbs.

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

Before it was abandoned and left to rust alongside the road, this riverboat starred in a John Wayne movie.

A tiny survivor of the Donner Party disaster.

The capitol city's oldest existing cemetery.

The California capital city once stood 10 feet lower than it does today.

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

An eccentric home stands out in an otherwise average neighborhood with mosaics, mini topiaries, and kinetic sculpture.

Cadillac where country's first big star was found dead.

The whimsical construction on the roof has given rise to many a Montgomery myth about its contents.