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

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

The top of a giant mesa, just outside of Amarillo, appears to float in the sky above.

The Grand Canyon of Texas.

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

In Paris, Texas they have their own Eiffel Tower, it just has a cowboy hat on it.

The highest point in Louisiana, Driskill Mountain at 535 feet above sea level.

The only international border marker within the United States.

Where Elvis Presley received his first Army buzz cut.

These waterfalls can be twins or triplets, depending on how much it's rained recently.

In the Ozarks, a waterfall shoots out from a glorious hole.

This impressive ledge seems to float above the Upper Buffalo Wilderness.

The highest waterfall between the Rockies and the Appalachian Mountains.

The final remnant of the Arkansas zinc industry is this historically protected ghost town.

An abandoned early-20th-century boomtown sits within the Calico Rock city limits.

An underground river pushes more than 200 million gallons out of this Missouri spring every day.

The seventh largest spring in the world.

An unexpected sinkhole in a desert flat within Gold Butte National Monument.

The highest concentration of petroglyph sites in Gold Butte National Monument, plus an improbable early 20th-century dam.

The Wonder Road aka Doobie Lane, a mile-long strip of dirt road filled with folk art.

A ghost town that was wiped out by a flood in 1940.

An internationally-recognized dark sky sanctuary lies in northern Nevada, near the Oregon line.

A little-known occurrence of fossil wood in northern Washoe County, Nevada, near the Black Rock Desert.

Many generations of travelers have passed through the steep, smooth walls of this canyon.