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.

The highest point in South Dakota contains the ashes of Valentine McGillycuudy, the "Holy White Man."

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

The oldest extant wooden jail in South Dakota and possibly the United States. 

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

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

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

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

This Great Plains museum pays tribute to both the prosperity and tragedy of the North American fur trade.

America's largest man-made forest was planted in an effort to bring back the past.

An experimental, automotive replica of Stonehenge.

A small Wyoming town is home to the state's oldest-operating soda fountain.

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

In the early 1900s, hundreds of Black Americans found opportunity in this now-abandoned rural community.

On the edge of grassland in northeastern Colorado, these rock formations are some of the few remnants of a high plain that has eroded away over millions of years.

This "zoo" is a cross between a junkyard and a sculpture garden, featuring animals you won't see anywhere else.

Here, at the "world's longest art gallery," you'll find forty miles of ancient petroglyphs and pictographs.

This ancient cave is home to a museum, bar, and is filled with fluorescent minerals.

A futuristic temple of light uses prisms and rainbows to create an atmosphere of peace.

A clear blue swimming hole with hidden caves, still unexplored.

Over 50 historic windmills whir away at this outdoor museum.

This refurbished gas station is one of the oldest in Texas, located on the original Route 66.

The old Route 66 town straddling Texas and New Mexico died along with the Main Street of America.

A popular swimming hole that hides one of America's most deadly diving spots.