This beautiful ancient site is dotted with perforated sandstone pillars considered sacred by some Native American groups.

An entire city block built completely out of petrified wood.

A monument to the forgotten French explorers and their landmark expedition.

This erect, phallic geological spire wasn't always named so domestically.

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

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

Dedicated to the history of the 1,000 nuclear missiles that once covered the Great Plains.

Abandoned businesses, homes, and rusted cars are all that remains of this stopover town.

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

The first declared National Monument in the United States.

Despite repeated attempts to make it work, this former mining town is now nothing but dust and memories.

The crumbling structure is a rare surviving relic of the area's bygone mining industry.

The world's largest mountain carving could fit all of Mount Rushmore inside it many times over.

Hidden behind Lincoln's head is a 70-foot-long chamber containing enamel plates documenting American history, sealed in a teakwood box in a titanium vault.

An antique Beechcraft airplane serves as a giant windsock for people driving through the blustery open country of eastern Wyoming.

A place where the laws of nature seem to have gone completely berserk... but of course haven't.

One of America’s oldest and spookiest hotels, thanks to the residency of ghosts, dead presidents, and Alfred Hitchcock.

Thanks to a loophole in property ownership, this alleyway has become a cacophonous street gallery.

Every president in history is immortalized in bronze in downtown Rapid City.

Yes, this monument is aware that it is about 20 miles away from the actual center of the United States.

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

This geodesic gallery holds a collection of painted spheres that make traditional canvases look lazy by comparison.

A cemetery housing wild west legends in South Dakota.