The quiet canyon has a tumultuous history involving a doomsday cult.

A desert ghost town—occupied for only 12 years—was once home to more than 500 silver mines.

A volcanic tunnel illuminated by natural skylights offers a shaded respite from the desert sun.

This private residence was the template for one of the most beloved television homes of all time.

Golden Gate Park's historic collection of plants.

Costumed elves and mountain bikers co-exist peacefully at this abandoned Christmas-themed adventure park.

This concrete tangle of square pipes has stood as a proud thorn in the city's side since the '70s.

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

A multimedia experience that chronicles the atrocities of racism.

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.

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

The "world's biggest dinosaur" once housed a creationist museum in its abdomen.

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

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.

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

San Francisco's urban bison herd has persisted in the face of extinction, development, and disease.

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.

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

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

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

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

The last remaining relic of San Francisco's glittering 1915 Panama Pacific Exposition.