Inside this old mill is a collection of images that will always remain frozen in time.

This charming woodland trail is peppered with poetry.

A wonderland of caves in eastern Iowa.

One of the largest private collections of fossils in the world.

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

The history of the treatment of mental illness, illustrated in all its gory detail, and housed in an asylum.

The notorious couple camped at this site after a bloody shootout with police.

A half-mile long and three stories high, this bridge over the Des Moines River Valley mimics a descent into a mine shaft.

A cemetery housing wild west legends in South Dakota.

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

Mining town from the late 1890s, once home to Calamity Jane.

Long before guestbooks and hotels, frontier travelers signed their names on this rock face.

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

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

The largest hot spring in the United States is, as the name suggests, a stunning show of natural color.

One of the highest points in Bexar county offers birdseye views of San Antonio and a four-story stone tower.

The summer home of the largest colony of bats in the world.

This improbable contraption was passed down through five generations of industrious Tennesseans.

An icy lake tucked among jaw-dropping alpine panoramas.

Trek up this glacier before it disappears.

Unable to build support structures on glaciers, the engineers for this tramway were forced to design a unique system.

According to a local legend, this peculiar mountaintop rock formation is actually a demon that was turned into stone.

This stunning natural double arch, the largest in the Alps, went undiscovered until 2005.

The second-largest natural arch in the Chartreuse Mountains.