Nature's biggest mammal swims in landlocked Oklahoma.

One believer transformed a local curiosity into proof of Vikings on the Great Plains.

A whimsical tower with a spiral staircase, inspired by the Space Age and the Möbius strip.

One of the world's largest pyramids stands within El Mirador, the "lost city of the Maya."

This neon blue river gets its color from a unique mix of bacteria and volcano minerals.

This Costa Rican topiary park is a surreal garden of unearthly delights.

The crumbling remains of a once-grand building.

The youngest volcano in Central America.

This unassuming layer of clay boasts an out-of-this-world origin story.

A clear blue swimming hole with hidden caves, still unexplored.

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

A blacklight journey through a celestial art exhibit.

Wee (and not so wee) footprints that insects and reptiles of the Paleozoic Era left behind.

The final resting place of the living embodiment of the famous Forest Service symbol.

In a largely deserted ghost town, a little brick building recalls its history as a gold rush hub and haven for outlaws.

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

A warm desert spring holds one of the rarest species on earth.

A one-of-a-kind sundial at the Very Large Array honors a radio astronomy pioneer, incorporating the original piers from his breakthrough radio telescope.

This popular pitstop lives up to its name.

In the remote high desert of New Mexico, a strange array of poles beckon fury from above.

A frozen oasis lies beneath the scorching New Mexico desert.

For those going through a life transition, a place to leave behind a piece of your former self.

The eroded core of an ancient volcano is now accessible by a short hike.

A mysterious spirit totem at the edge of Navajo lands.