The ghostly remains of an accidental sea.

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

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

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

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

A mysterious spirit totem at the edge of Navajo lands.

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

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.

Dyed by iron oxide over centuries, these sandstone rocks rise thousands of feet into the sky.

This mysterious petroglyph evokes the ancient swastika symbol but was later vandalized with the more troublesome Nazi one.

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

The drama of nature in full effect in this Nevada State Park.

Seemingly grown on some other world, these New Mexico rock formations look like a disused science fiction set.

These Pre-Columbian petroglyphs contain representations of birds, deer, hunters, and even some early Native flute players.

A preserve with 75,000 ancient drawings remains the realm of public – not just scientific – exploration.

A sign at the end of the Santa Monica Pier marks the traditional end of the legendary American highway.

An abandoned 1920s-era stretch of cabins now overshadowed by the 66 Motel.

400 million-year old limestone caverns nestled in the Ozarks served as shelter and a hideout for cultures throughout North American history.

When you can afford only half a road, you build only half a road.

A religious-themed park filled with folk art to bring biblical stories to life that fell into disrepair and now being restored.