Curious cave that stays a cool 56 degrees all year long.

The ghostly remains of an accidental sea.

Crystal clear lake with a shoreline of travertine located in a Colorado canyon.

Ninety feet off the valley floor is an ancient dwelling put under protection of the U.S. government by Teddy Roosevelt.

This secluded aqua waterfall in the Grand Canyon is the perfect swimming hole, and the Havasupai tribe's fiercely protected natural wonder.

The largest natural travertine bridge in the world is nestled in a small canyon in central Arizona.

The only way to see Pittsburgh is from the top of this lookout point, just like the ancient members of the native peoples did.

The highest point in Arizona is an oddly snow-topped peak within the otherwise arid state.

A mysterious spirit totem at the edge of Navajo lands.

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

One of the world's oldest and most massive living organisms is a grove of quaking aspens.

Sandstone rock formations that look like they belong on the cover of a progressive rock album.

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

A phenomenal assembly of pueblos in New Mexico is the most complete example of ancient ruins north of the border.

On the side of a remote mountain, a stone face bearing an inscription of mysterious origin.

This centuries-old pueblo church houses the body of a Franciscan friar who is said to be a rare "incorruptible" corpse.

Years of archaeology, just chillin' by the water cooler.

The final resting place of American icon Buffalo Bill, and a museum that aids in telling his tale.

Wondrous sandstone hoodoos where Native Americans collected clay for pottery, 9,000 years ago.

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.

A coastal rock outcrop with mysterious inscriptions variously attributed to Native Americans, Portuguese, Phoenicians, Norse, and more.

The kind of mixed-up place that drives archaeologists crazy.

These mysterious petroglyphs in Vermont reflect a troubled history in the treatment of Native American culture.

This beautiful ancient site is dotted with perforated sandstone pillars considered sacred by some Native American groups.