The world's longest known cave system.

A museum in Mississippi celebrates the history of Coca-Cola and the man who brought it to the masses.

This iron and wood Civil War city-ship was the first vessel to be sunk by an electrically detonated torpedo.

The site of the Scopes Trial contains a small exhibit dedicated to the famous case.

This historic train station has been converted to a locomotive themed hotel.

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

Wisconsin's most celebrated export gets the royal treatment on I-94.

This circus town museum recognizes the outstanding clowns of history.

A large circus museum with summer performances.

One of the largest collections of wildlife art in the United States, built into the side of a cliff in rural Wyoming.

One of nature's most well-scheduled phenomenons resides in Wyoming's Yellowstone National Park.

The largest hot spring in the United States is, as the name suggests, a stunning show of natural color.

A beautiful geyser under environmental threat.

The first declared National Monument in the United States.

The oldest continuously occupied public building in the United States.

Wedding chapel's mysterious spiral staircase said to be miraculously constructed.

The official atomic museum of the United States explores the explosive and productive history of a much maligned energy source.

"I did this all while you were watching TV."

On the outskirts of a reborn ghost town, a decaying post office remembers the bad old days.

See massive fossils that are over 200 million years old in northeastern Arizona.

Steinbeck's old stomping grounds, immortalized in Cannery Row.

The oldest U.S. Government building in California, and it's State Historic Landmark #1.

One of the most elaborate displays of Jellyfish is on display at the aquarium.

The oldest continuously operating church in California.