This 4,000-foot-diameter hole is touted as "the most well known, best preserved meteorite crater on Earth."

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

A museum dedicated to the alleged Roswell Incident.

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

These remote Florida islands have a history of sea turtles and sunken treasures, and one of the world's largest coastal brick fortresses.

The famous boat that once ferried Bogart and Hepburn still floats in Key Largo after being abandoned for years.

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

A monument celebrating the idea of reaching inaccessible places.

The only diamond mine in the world where you can keep what you find.

A six-ton, 12-foot-tall concrete prairie dog is touted as the largest in the world.

This historic national park is covered in the stunning ruins of red rock pueblos.

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

This massive roadside mascot was the first version of the giant to illustrate his butt.

The world's largest piece of copyrighted artwork.

From economic backbone of a community to deadly diving hole, these former stone quarries are now a park for rock climbers and graffiti artists.

The homestead of American patriot John Adams.

The world's largest mountain carving could fit all of Mount Rushmore inside it many times over.

The world's largest Holstein cow.

Massive still life just off the highway in Kansas.

America's oldest archaeological site or a muddled case of wishful thinking.

An experimental, automotive replica of Stonehenge.

A sculpture made of 10 Cadillacs as a monument to the "Golden Age" of the American automobile.

The only road through the heart of Glacier National Park.