Mysterious glowing orbs float through the desert night.

An enormous pink granite batholith, long attributed with spiritual powers by the Tonkawa Indians.

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

A modernist landscape of water and sci-fi concrete.

An emerald-green grotto just a short trip from Austin.

Over a dozen Native American earth mounds dating back over 2,000 years dot this Tennessee archaeological park.

All you ever needed or wanted to know about America's favorite whiskey, but not a drop to drink.

The first full-scale tunnel built in America is short but scenic.

A Memphis park where you can walk the whole Mississippi River in one go.

Every day a troupe of pampered water fowl walk the red carpet to their favorite fountain.

Labor provided by Great Depression-era programs restored these 25,000 acres in Tennessee.

Visit this playground of waterfalls, caves and sinkholes.

For two weeks every June, fireflies in the Smoky Mountains perform an astonishing light show.

This monument remembers one of the manliest men of the frontier who fought a grizzly before dragging himself 200 miles to safety.

An entire city block built completely out of petrified wood.

This Wild West attraction is alive with glitching automatons.

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

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

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 small museum dedicated to the painful memory of segregation is essentially a time capsule.

This psychedelic tromp l'oeil seems to be beckoning drivers to crash into a wall.

Mysterious stone tower featured in many alternative histories of the New World.

Three and a half miles of cliffs, rocky beaches, Gilded Age mansions and 40 Steps to nowhere in particular.

A rugged lava field dotted with molds of the ancient pines that were growing when the volcano erupted.