A multi-storied adobe complex has been inhabited for more than a thousand years.

A short hike into the mountainside forest reveals a decaying 1890s town.

A small flooded ghost town with a few scattered structures remaining.

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

San Francisco Bay's ghost town.

A phenomenal assembly of pueblos in New Mexico is the most complete example of ancient ruins north of the border.

A once grand hotel is being retaken by the wilderness it once capitalized on.

An abandoned village that doubled as "The Hunger Games"' post-apocalyptic wasteland is up for grabs.

The longest living non-clonal organisms on Earth.

The lush coastal city of Astoria is riddled with forgotten secret sidewalks.

A sculpture made of 10 Cadillacs as a monument to the "Golden Age" of the American automobile.

European castle ruins in an American state park are actually the product of death and grief.

Ruins of the elaborate house where the enigmatic costume designer threw glamorous parties for New York's theatrical elite.

An unassuming secret door once led to a legendary watering hole.

Brightly colored 30-foot-tall totems light up the desert sky just outside Las Vegas.

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

A picture-perfect town, perfect for blowing up.

This charmingly homemade amusement park has been growing for 40 years.

One man's vast collection of artifacts and ephemera from matchbooks and postcards to vintage neon signs and cars.

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

Ninety feet off the valley floor is an ancient dwelling put under protection of the U.S. government by Teddy Roosevelt.

Explore 10 acres of environmental sculptures.

Frank Lloyd Wright's most iconic home dangles over a Pennsylvania waterfall.

A religious-themed park filled with folk art to bring biblical stories to life that fell into disrepair and now being restored.