When ecosystems collide in the arid Southwest.

This nearly abandoned town was once a thriving mining community until a series of fires.

A preserved 18th century homestead in Western Pennsylvania marks the spot where the Whiskey Rebellion began.

This red-eyed chrome beast pays homage to the popular modern myth of West Virginia's insectoid monster.

The site of the one and only battle of Lord Dunmore's War.

One day a year it is legal to jump off of this astoundingly tall bridge that spans an Appalachian gorge.

An abandoned coal mine reached by a steep hike.

Once connected to the outside world by a single train track, this ghost town is looked after by the National Park Service.

This functioning mill was built in the 1970s using parts from several other West Virginia mills.

This Pennsylvania cave holds evidence of the oldest known inhabitants of North America.

Nothing says indulgence like a 1,500-pound chocolate castle.

Built in the 1850s, this church was of the first five churches constructed in Harper's Ferry.

The last holdout of a pre-Civil War rebel who took the matter of slavery into his own hands.

A giant time capsule not scheduled to be cored until 2040.

Spectacular mineral formations fill these caves, which have been used for everything from smoking meat to stashing illicit liquor.

Near-constant high winds deform the trees on Spruce Knob, the highest point in West Virginia.

Take a steam-powered ride straight out of the past on this Appalachian rail line.

This rural community has attracted both scientists and techno-refugees due to its federally-mandated lack of technology.

The world's largest fully steerable radio telescope.

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

The penultimate and final resting places of British General Edward Braddock—minus a few bits and pieces.

This university transit system is a 1970's vision of the future.

A well-preserved relic of the industrial age steel and iron works that dotted West Virginia.

This claimant to the title of "smallest church in the 48 states" doubles as an equally tiny, quasi-post office.