400 million-year old limestone caverns nestled in the Ozarks served as shelter and a hideout for cultures throughout North American history.

A creepy sculpture of a decapitated head invites viewers to see St. Louis through its empty eyes.

This abandoned prison castle has become an imposing gallery of graffiti art.

The world's largest man-made underground caverns offer unparalleled underwater wonders.

European castle ruins in an American state park are actually the product of death and grief.

A wonderland of caves in eastern Iowa.

An Iowa town celebrates its heritage with the tallest working Dutch windmill in North America.

Chilly air billows out from the entrance of an abandoned mine on a steep hillside, providing a refuge for Ice Age fauna and flora.

For just a few bucks, this Iowa funicular will let you feel like an 1800s fat cat.

Home with Gothic windows featured in a famous painting.

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

Before its closure in 2002, this South Dakota mine was the largest and deepest gold mine in Western Hemisphere.

Despite monuments in other locations, this spot in a South Dakota field is recognized by the U.S. National Geodetic Survey as the center of the 50 states.

The cliff and rock formations are made out of Sioux Quartzite.

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

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.

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

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

The ravine where Jesse James supposedly performed an impossible jump to evade capture.

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

This small, independent museum documents the unique culture of Deaf people in the United States.

This tiny old water tower once doubled as a makeshift jail.

Once an ancient sea, this landscape of rocky ravines is filled with the fossils of ancient marine life.

Journey up the capitol building's cupola for an amazing view of Topeka.