A collection of massive stacked rocks in Texas includes a snarky note on the benefits of modern technology.

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

This is one really big nut.

This fast-food outlet is the only space and UFO-themed McDonalds in the world.

A museum dedicated to the alleged Roswell Incident.

Two massive and unstable sinkholes are yearning to unite, and their consummation could be catastrophic.

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

A dangerous narrow-gauge railroad once traced a route through this striking canyon.

Two tall rocks sit at the center of this site, once the home of a large Ancestral Puebloan community.

The site of the gruesome massacre—and maybe cannibalism—of five men, a tragedy that made Alferd Packer infamous.

This National Natural Landmark is one of the best examples of a “mass wasting” in the world.

A short but powerful waterfall resides amid Colorado’s Great Sand Dunes.

When ecosystems collide in the arid Southwest.

Unlike most arches, this geological oddity formed in a volcanic dike.

Historic, 19th-century wagon wheel ruts cut into soft volcanic ash.

The temporary burial site of the man who shot and killed Jesse James.

A fake mine that was made using real mining techniques which is also used as a community center.

Take a self-guided tour through one of Colorado's most elevated mining districts.

This once-popular otherworldly landscape was formed by one of the largest volcanic eruptions in history.

This haunted hotel built on natural springs once served as a hospital for a quack doctor promising a cure for cancer.

The Old Mill shown in the opening credits of “Gone With the Wind” is actually fairly new, and was never a mill at all.

A short boardwalk through a swamp leads to the spot from which the Louisiana Purchase was surveyed.

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.