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

The secret city built by the Manhattan Project.

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

A geological mystery on Camelback Mountain.

The eroded core of an ancient volcano is now accessible by a short hike.

Ninety feet off the valley floor is an ancient dwelling put under protection of the U.S. government by Teddy Roosevelt.

Take a dip in the world's largest mineral hot springs pool.

The huge collection of paintings of the American West is one of Denver's best-kept secrets.

Despite being one of the most photographed vistas in the Rockies these twin peaks are rightfully known as the "Deadly Bells."

The ancient dwellings of the Puebloans, located in the cliffs of majestic mesas.

Once the most flame resistant building in the country, the South Carolina Historical Society building was almost burnt down in a fire.

Thirteen pastel palaces in downtown Charleston add a gorgeous splash of color to the city.

Tour the oldest unrestored plantation house in America that is open to the public.

Charleston's historic city jail once held everyone from pirates to Civil War POWs.

South Carolina's last remaining slavery auction house is now a museum devoted to its own tragic history.

The museum chronicling a treasure hunter's dream, fulfilled.

"We Seceded Where Others Failed."

An icon among Florida's pre-Disney tourist attractions, just west of Orlando.

The highway's southernmost spot is a beloved local attraction.

This spiny beast guards an artist's village while vying for the title of largest lobster in the world.

St. Augustine's record-setting narrow street was designed to protect against pirates.

A building so large that it has its own weather.

This abandoned NASA launch site is now a memorial to a trio of astronauts who were killed there.

The walls of America's oldest masonry fort famously "swallowed" cannonballs.