The world's longest known cave system.

Once an ancient sea, this landscape of rocky ravines is filled with the fossils of ancient marine life.

A landscape of massive spherical boulders are the main attraction in this Kansas State Park.

The United States's largest hand-dug well is topped with a state-of-the-art museum.

A half-mile long and three stories high, this bridge over the Des Moines River Valley mimics a descent into a mine shaft.

A set of tall pillars and alcove-like rooms that are significant to the Miami people of Indiana.

Lions and tigers and leopards, servals, pumas, bobcats, lynxes, and ocelots... oh my!

A creek tumbles over a series of step-like rocks to create this scenic water feature.

These falls, sometimes called the "Niagara of the West," still put on a good show at the right time of year.

This set of hot springs also comes with fantastic views.

This narrow coastline trail through the dense Kauai wilderness is among the most beautiful and dangerous in the world.

A cooled lava flow from the Haleakalā volcano formed these surreal-looking columnar basalt structures.

A prehistoric landscape hidden in the cliffs of Maha'ulepu.

The island of Lanai in Hawai'i is a paradise for cats and cat lovers.

Brick walkways weave through more than 500 palms and cycads, representing 150 species from around the world.

These craggy limestone outcrops offer a glimpse at a unique piece of Florida geology.

You’ll feel like you’ve gone through the looking glass at this contemporary art museum filled with glass sculptures of every size, shape, and color.

Wading through a small lagoon reveals a secret, wild stretch of pristine beach.

The first custom-designed building to showcase the works of Dale Chihuly is a wonderland of glass and light.

A secret, rocky playground hidden amongst the plain white beaches of the Florida coast.

A peaceful, unique botanical garden complete with waterfalls, mini islands, and swans.

This ancient octopus-like tree was saved from destruction thanks to shady reporting.

The behemoth beasts engaged in an epic battle is the second-tallest statue in the contiguous United States.

A giant 400-acre preserve in North Florida for displaced wolves.