These remote Florida islands have a history of sea turtles and sunken treasures, and one of the world's largest coastal brick fortresses.

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

Trek through the jungle on a boat and a swinging bridge and you'll be rewarded with these refreshing, if pungent, mineral pools.

This beautifully deceptive waterfall is something far different from what it appears to be.

Dramatic river bend surrounds a natural red-rocked pedestal.

Amid lush greenery, a man-made channel peppered with graffiti that dates back to 1881.

These azure waters were thought to lead to the Mayan Underworld.

A magical sinkhole on the Yucatán Peninsula is adorned with mini waterfalls and hanging vines.

Witnessing the might of this dessert-colored desert waterfall is a rare, powerful treat.

Three sinkholes filled with warm, crystal-clear water reached by a horse-driven cart on an old train track through the jungle.

A lovers' beach, tucked below the surface of the island, provides a safe haven for romance.

Visit this playground of waterfalls, caves and sinkholes.

One of the few places where you can visit a cenote and Maya ruins at the same time.

The mysterious wonder of an underground waterfall is illuminated by multicolored lights.

At this Denver landmark, the meals are compulsory, the sopapillas are complimentary, and the insanity is everywhere.

The first full-scale tunnel built in America is short but scenic.

A humid oasis combines recreation with exploration in a unique underwater cavern.

This naturally-sourced hot spring is now home to a clothing-optional resort.

A lake at the bottom of the ocean.

Warm water springs inside an astounding canyon.

The development of this cliffside waterpark is representative of Mexico's history of co-op tourism developments.

Hidden in the New Mexico desert southeast of Roswell, nine small deep lakes formed inside sinkholes.

Foragers once flocked to this big beautiful bayou to hunt for pearls.

William Faulkner kept his beloved estate wild and untamed.