The world's longest known cave system.

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

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

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

The highest point in Tennessee, Clingmans Dome bears witness to the ravages of one type of insect.

The granddaddy of all tourist traps, built on ice water, jackalopes, and a giant dinosaur.

One of America's first dinosaur parks gives a window into Depression-era paleontology.

The first declared National Monument in the United States.

One of the only Florida forts to remain in the hands of the Union all through the Civil War still stands as a historic stronghold.

Pensacola's UFO home has withstood many hurricanes—just as the experimental 1960s design intended.

The second-largest ceremonial mound in the United States is an artificial hill that is loosely shaped like a pentagon.

A ghost town that held steady longer than most, but finally gave up the ghost.