The cluster of boulders near Fort Irwin is covered in military insignia.

A ring of creosote bushes that are estimated to be 11,700 years old.

Built following the War of 1812, this fort has withstood hurricanes for centuries.

Moving, mind-blowing metal sculpture work of an outsider artist.

This angular brutalist playground turns playtime into modern art time.

A wild west land agreement was etched right onto this historic Idaho stone.

A swamp and garden tour featuring local wildlife and exotic botanical specimens from around the world.

A historic hotel in an old California railroad town with a rowdy reputation.

A wacky, UFO-shaped house in a suburban neighborhood.

The abandoned ruins of America's first private zoo are open for exploration in the Catskills.

This fort down the Potomac from Washington, D.C. was once the only defensive fort protecting the capital.

This small hut in the middle of a parking lot was once the wooded sanctuary of the 'Hermit of Montrose.'

Under a playground is a little-known sealed train tunnel that likely contains the bodies of workers trapped by cave-ins.

A brick-paved former section of the historic coast-to-coast highway.

Tucked behind New Jersey's abandoned Gingerbread Castle lie the eerie ruins of a once-flourishing paper mill.

A mining town, now abandoned, was built in a canyon so narrow that the railroad ran right through the hotel lobby.

This historic bridge has weathered fires and floods and still stands, now abandoned, where it has stood since 1874.

This former asylum for Black Americans is haunted by its history of violence and racism.

Nevada's largest cactus collection stands outside a candy mogul's small factory.

The highest peak in Utah is the hardest to reach, but only if explorers choose the hard way.

Unknown to many, this sparkling turquoise lake hides amid Oregon's snowcapped mountains.

A pier that used to act as a busy ferry dock is now a decaying favorite of local fisherman and urban artists.

This blowhole is supposedly caused by a trapped monster.

The concrete shell of an industry giant remains as a playground for graffiti artists, auto scrappers, and paintball warriors.