This stately 19th century library pushed architectural boundaries at a time when the public library movement was just taking off.

Bizarre Cavern.

Bubbling up from deep underground is the warm crystal clear water that fills the Warm Springs Pools, America's oldest spa.

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

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

Beautiful waterfalls grace a canyon visibly torn by a violent tornado.

A full-scale replica of a 1774 colonial settlement in Kentucky.

Moonbows over Kentucky.

The world's longest known cave system.

In the Shawnee National Forest, amazing rock formations peer through the treeline.

This historic church is named for abolitionist Henry Ward Beecher and the ruse to arm his fellow abolitionists.

A landscape of massive spherical boulders are the main attraction in this Kansas State Park.

Other-worldly rock formations and ancient fossils abound in this unique stretch of Nebraska badlands.

A rancher expanding a natural spring for his cattle came up with bones – lots and lots of them.

Site of the 1879 Cheyenne Outbreak and the site where famed Sioux chief Crazy Horse met his fate.

This replica stave church looks like a piece of Norway was simply plopped down in South Dakota.

A waterfall 600 ft. inside a mountain, once the bane of gold miners, is now a spectacle of nature.

This prehistoric sinkhole lured exclusively male mammoths to their death, much to the delight of science.

A rapidly disappearing glacier filled with extinct grasshoppers, perfectly preserved in the ice.

The highest point in Montana is as rugged and singular as the state itself.

Native Americans built this circle of stones, which was used to predict astronomical events.

One man's ambition created this psychedelic log home.

An apocalyptic seismic event creates a deadly chain reaction that ends with a 6-mile long lake developing within weeks.

New fungal and bacterial species call this deadly lake home.