When ecosystems collide in the arid Southwest.

Strange red rock formations that have been attributed to a higher power for hundreds of years.

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

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.

A controversial memorial at the place where Captain Cook met his violent end.

Earth's tallest volcano is sacred to Native Hawaiians, and home to a dozen world-class observatories.

The marker offers a rare chance to be in four U.S. states at once, though there's some controversy over its geographic accuracy.

Come for the speed, leave in love with the desert.

The hike through a narrow river flanked by the 2,000-foot-tall walls of Zion Canyon is one of the best in the world.

Giant, natural amphitheaters made of delicate geological formations called "hoodoos."

South Dakota's oldest operating brewery is housed inside a historic firehouse.

A fitting attraction for the corn capital of the world.

Home to the deepest rift anywhere on Earth.

The Grand Canyon of Texas.

The second-largest cave chamber in the world was discovered in 1898 by a 16-year-old and a friend known as "Pothead."

Explore the largest pure gypsum deposit in the world, and go dune sledding while you're at it.

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

Walk through the actual strap iron cells and solitary chambers of Arizona Territory’s first prison.

A wild west cemetery in Tombstone, Arizona, provides a window into the Old West.

Ancient pueblos built into the base of a natural canyon wall.

This public square capitalized on a single Eagles reference to bring some life back to an Arizona town.

A toxic ghost town sitting atop a massive coal fire.