Bizarre Cavern.

This Tennessee museum is dedicated to a tragic railroad hero who inspired the famous ballad that bears his name.

This stone incorrectly marks the 35th parallel, causing some territorial kerfuffles.

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

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

This funicular railway rumbles along for a mile up the nearly vertical face of Chattanooga’s Lookout Mountain.

The mysterious wonder of an underground waterfall is illuminated by multicolored lights.

Home of an evil witch famous within southern folklore.

Enormous lake at the bottom of a unique cave system.

This road in the Great Smoky Mountains was supposed to assuage a displaced community, but ended up a $52 million dead end.

This cave column thousands of feet below the earth’s surface is rightly named for one of the most colorful park rangers in history.

This building is a recreation of the gatehouse that separated Los Alamos from the outside world during the era of the Manhattan Project.

High in the Sacramento Mountains, a facility dedicated to studying the sun.

The final resting place of the most famous outlaw in the Old West.

The ruins of this abandoned fort now stand as a picturesque reminder of America's march West.

A frozen oasis lies beneath the scorching New Mexico desert.

Home of the International Space Hall of Fame.

Thousands of pieces of art have been carved into the rock at the site of an ancient volcanic eruption.

Twenty-seven massive radio antennas on the high plains of New Mexico search for life on other planets.

This volcano rises like a giant anthill from the plains below, with a road spiraling up to the rim.

More than 21,000 images fill this overlooked gem of a prehistoric site.

This quirky hot springs town known to locals as "T or C" was named after a radio show.

A unique geological area spiked with wind-carved rocks that resemble teepees.

A small metropolis of Pueblo cave dwellings have been carved right into the hillside of this national monument.