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 Old Courthouse takes visitors on a captivating trip through St. Louis' timeline.

One of the world's earliest skyscrapers.

This tree has witnessed nearly 1,000 years of history.

Inside this striking glass building, visitors can see thousands of dinosaur fossils in the positions that nature deposited them more than 150 million years ago.

This old abandoned sign flickers to announce a motel that isn't even there.

The location where the iconic movie character declared it was time to go home.

The handsome statue is a tribute to the post riders who traversed 52 miles of tough Arizona terrain.

This massive, ancient canal system was built using only sticks and stones.

Site of a tragedy on the Oregon Trail.

This reclusive Hopi village in Arizona has been continuously populated longer than anywhere else in America.

One of the most extensive and well-preserved collections of dinosaur footprints in North America.

A mysterious spirit totem at the edge of Navajo lands.

Home to a forest of whimsical pygmy Coast live oak.

The entire history of the U.S. Space Shuttle Program is painted on an enormous roadside water tank.

The illuminated falls are a gem in North Cascades National Park.

This sci-fi gazebo located in a Washington power town is made from old bits of industrial electrical equipment.

What began as a prominent Burning Man art piece is now an iconic symbol of downtown Reno.

The second-largest giant sequoia in the world.

This vast and otherworldly landscape is one of the largest dune complexes in North America.

A geological mystery on Camelback Mountain.

This balancing rock is one of Utah's most unusual geological formations.

An abandoned amusement park based on the popular 1940s Red Ryder comic strip.

The folks at the Devil's Rope Museum want you to get hooked on barbed wire history.