The atmospheric road was never meant to be so creepy.

The ruins of this medieval castle in Northern Ireland have inspired artists from C.S. Lewis to Led Zeppelin.

Perhaps the most spectacular grotto along the Algarve coastline.

The biggest cave system in the Arabian Peninsula is home to a rare variety of blind fish.

A remarkably well preserved tower dating all the way back to the Iron Age.

A perfectly circular lake is formed by the crater of an ancient underwater volcano.

This small cave in the center of Isla Colon doubles as a sanctuary.

The rusting hulk of a hand-powered, nearly 160-year-old submarine abandoned in 1869 due to the ravages of decompression sickness.

Who needs fancy modern water slides when this giant North Carolina rock works just as well?

These strikingly barren, rolling red hills were caused by bad farming practices.

On this stunning Scottish island, you can walk in the footsteps of dinosaurs.

The mystery of this small, brick pond eluded its possibly only investigator until his death.

This archaeological site built into a tuff outcrop is filled with rock dwellings, the ruins of a medieval castle, and a necropolis.

This picturesque Umbrian city has a subterranean side that has long remained hidden.

Nine caves filled with recently-discovered archaeological finds under the houses and the streets of the most ancient district of an old town.

An explosion of natural color known as "the river that ran away from paradise."

A remote candy-striped mountain in the Peruvian Andes straight out of the pages of Dr. Seuss.

A island reachable by a causeway at low tide is possibly one of the earliest Western European locations to be identified in text.

The mysterious, fantastical woodland inspiration for "The Lord of the Rings."

On the Oregon coast there is a natural hole that seems to be draining the sea.

The centuries-old trees lining both sides of this dirt road may become Madagascar's first natural monument.

The longest hedge maze in the world.

Step inside the first house designed by Catalan architect Antoni Gaudí, considered to be one of the first Art Nouveau buildings.

These ancient sunken lanes were naturally tunneled into the soft ground by countless footsteps.