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

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

This portion of a lovely Belize beach is infested with (harmless) sharks and rays.

A massive underwater sinkhole made famous by Jacques Cousteau.

The religious shrine that Pablo Escobar's men would allegedly visit before completing a mission.

The hellish conditions of this abandoned mine that snakes beneath the Pacific Ocean gave it its diabolic name.

Within the former ghost town of Cisco is a carefully restored tiny town with one resident and its own art residency.

This sandstone building is a relic of the Overland Trail.

This canyon is named for a unique geologic formation where the river vanishes underground near the mouth of the canyon and reappears farther down.

A spectacular overlook of the Little Grand Canyon of the San Rafael River, a deep sandstone gorge streaked with orange, red and white in a remote, uncrowded part of Utah.

This rugged area of red rocks and arches is often considered one of the most beautiful places on Earth.

A 90-foot-tall psychedelic "tree" on the side of the highway has baffled passersby for decades.

Formerly the world's largest, this Willy Wonka-esque contraption runs 24/7.

The world's largest dead polar bear, immortalized by taxidermy and Hunter S. Thompson.

A volcanic fissure over two miles long and up to 70 feet deep.

Small Nevada town embraced its designation as the "Armpit of America" with an Old Spice-sponsored festival.

This rustic old building is said to be the most photographed barn in America.

A quiet rock and botanical garden is the beautiful centerpiece of Fort Lewis College.

This unassuming building houses one of the world's most extensive collections of cars created by automotive legend Carroll Shelby.

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

One man's love for East Coast diner culture brought an entire eatery all the way from New Jersey to Colorado.

The highway's southernmost spot is a beloved local attraction.

A monument celebrating the idea of reaching inaccessible places.

The former home of the Nobel Prize-winning American writer is now home to dozens of six-toed cats.