This 140-year-old beacon off the Florida Keys marks the wreck of a Navy ship that once roamed the Caribbean hunting pirates.

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

Meet manatees face-to-face at this zoo for native species.

This ancient sinkhole-turned-healing-pool is a treasure trove of archeological discoveries and may even be the Fountain of Youth.

The scuba diving training facility was named for the steam that rises from the cave's chimney.

For divers and music lovers, the Florida Keys' Underwater Music Festival provides the best of both worlds.

An underwater statue of Christ blesses the depths off Key Largo.

A steep and winding road in the Yorkshire Dales passes by these deep natural potholes.

According to the Guanches, the aboriginal people of the Canary Islands, the king of evil lives inside this volcano.

Think you have a tough job? Try carrying 200 kilos through a cloud of sulfur down the side of a volcano.

Fire meets ice at the southernmost volcano on Earth.

This towering volcanic plug stands out among the dramatic formations that dot this otherworldly desert valley.

Take a hike to this unique rock formation formed by lava flows.

This granite rock face is named for the magnificent reflection that occurs when the sun hits it just right.

This unique formation is characterized by hexagonal basalt rocks stacked in unique formations.

Romania's "Red Ravine" is a little-known natural wonder that bears a resemblance to the Grand Canyon.

Crooked windswept pines give this old forest an enchanted and magical look.

A unique geological area spiked with wind-carved rocks that resemble teepees.

On the edge of the Valles Caldera National Preserve, these rock formations create an eerie landscape.

The 7,000-year-old calcium carbonate formation creates a magnificent natural bridge.

A beautiful red-faced slot canyon in northern New Mexico.

This maze-like slot canyon is a unique gem within an already fascinating geological area.

The highest point in Virginia can only be reached by passing through ponies and flowers.

Along the banks of the River Rhine lies a park that seems unassuming, but beneath the surface lies a long and fascinating history.