Although it appears much older, this castle-like tower is actually a Georgian-era folly.

One of the deepest blue holes in the world.

Cavernous opening completely encased in Karst limestone.

You may get stranded and everyone's peeing in the water, but at least there's cocktails!

The legend associated with these ruins understates the splendor of the mansion that once stood here.

A 220-foot deep watery drop-off, filled with marine life.

This island hill is strewn with boulders carved by shipwreck victims from the age of sail.

Uninhabited islet in the Caribbean is the sanctuary of giant lizards.

The rusted remains of a victim of Hurricane Ike.

A sinkhole known simply as "The Hole."

This popular tourist cave was ignored for almost 200 years before being mined into an attraction.

Under the desolate and windswept northern coast of Barbados stands a small oasis filled with sea anemones.

A hotly contested micro-nation off the coast of Montserrat.

Small church built in the 19th century for whites and slaves to worship together.

Legend has it this historic port was a popular hideout and smuggling spot for pirates.

Rumored to be the famed pirate's lookout tower, this historic stone structure is now just watching for tourists.

This huge pile of volcanic boulders hides a stunning network of secret grottoes.

Divers can encounter an abandoned warship encircled by a giant kraken submerged in the British Virgin Islands.

A mountain of conch shells created by centuries of fishermen.

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

A beach made of semi-precious green sand on the Big Island of Hawaiʻi.

What remains of the summer palace of King Kamehameha III.

This black shoreline is made up of exploded lava particles.

Earth's tallest volcano is sacred to Native Hawaiians, and home to a dozen world-class observatories.