The site of murders and Satanic cult gatherings.

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

Abandoned bridge hidden deep in the San Gabriel Mountains.

The "Fun Spot of the Desert" is now a haunting ruin, and a reminder that putting a water park in a desert is a bad idea.

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

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

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

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

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

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

This rare example of a "tidefall" is a spectacular drop from the cliffs down onto the beach.

Once thought to be the oldest living tree in the world, Methuselah was germinated before the Egyptian pyramids were built.

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

Aqueducts have dramatically changed this old lake, now home to tufa towers and its very own species of tiny brine shrimp.

This glamorous old building is said to have inspired the Tower of Terror.

Eons old volcanic activity created one of the most stunning rock formations in the United States.

A modern mechanical planetary system, part of a 10,000 year clock.

Trails through lava-carved tube-caves display sparkling bacteria and a rich history.

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

Carved by a waterfall in a hard-to-reach rock formation, this heart-shaped rock has inspired romantics for decades.

A collection of 20th-century automata, penny arcade games, and musical contraptions.

An essential stop before plundering, BYO Cutlass.

Quite simply the largest tree in the world (by volume).

One of the last remnants of the city's Chinese nightclub scene is now a dive bar selling killer mai tais.