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.

You thought Santa Claus didn't exist, but it turns out you were wrong.

The site of a 19th century "dream city" that almost rivaled Chicago before being swallowed by the Indiana sand dunes.

The longest navigable underground river in the United States is home to countless blind and albino animals.

The largest freshwater lake in the Florida Keys.

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

A monument celebrating the idea of reaching inaccessible places.

Island ghost town detailing Flagler's folly in building the Overseas Railroad.

Welcome to old Florida, where a 1940s mermaid show is still enchanting visitors.

Even with its slightly risible name this colossal cross is still able to inspire awe.

A mythical bird etched into the face of a rock doubles as the mascot for a nearby school.

River pirates, murderous bandits, and serial killers used this Illinois cave as their debauched hideout.

Once one of the world's great cities, Cahokia was a place of religious worship, trade and mass human sacrifice before being mysteriously abandoned.

The 80-foot tire that looms over Michigan's I-94 was once a Ferris wheel in the New York World Fair.

The fifth-longest suspension bridge the world, connecting one Michigan peninsula to another.

Largest tulip festival in America, includes fireworks, a parade, and a carnival.

Strange physical sensations and optical contradictions keep visitors coming back for more.

Island where motor vehicles are banned -- home to the only carless highway in the United States.

In the St. Francois Mountains in the Ozarks at 1,772 feet above sea level, Taum Sauk Mountain is the highest (and possibly oldest) peak in Missouri.

Giant granite rocks standing end-to-end like a train of circus elephants.

400 million-year old limestone caverns nestled in the Ozarks served as shelter and a hideout for cultures throughout North American history.