The only pollutant in the clear blue water is sunscreen.

The largest underground church in Europe.

This mountain fissure hides a secret path to a secluded mossy grotto within the rock itself.

A centuries old castle atop a dormant volcano houses museums devoted to both women and witches.

A gravity-defying "devil's bridge" that has a surprising architectural feature for its stability.

This scalding hot river was thought to be a myth until one geoscientist made it his quest to study the mystical waters.

This centuries-old Italian chapel hangs midway down a sheer cliffside.

The largest island on the great salt lake is home to curious creatures and strange stories.

An ancient stone fortress considered by many to be the eighth wonder of the world.

This medieval Italian town is a sheer (and beautiful) cliffside defense.

This natural French spring has been turned into a magical grotto by Roman and medieval constructions.

This complex of vertically-excavated Buddhist, Jain, and Hindu monolithic temples in India's Maharashtra providence illustrates a spirit of tolerance characteristic of ancient India.

High atop a Mexican rainforest mountain, this ancient pyramid once drew pilgrims countries away.

This crumbling folly looks like an enchanted left over from Middle Earth.

This elaborately decorated, fairytale-like Romanian royal palace is one of the most striking castles in Europe.

A Texas cave network is home to some of the world's most spectacular-looking and bizarrely named mineral formations.

An ancient neolithic tomb that only sees the sun twice a year.

A white Buddhist temple with a golden restroom.

The Grand Canyon of Texas.

Terrifically morbid cemetary and site of famous Paracelsus' grave.

Curious cave that stays a cool 56 degrees all year long.

The convergence of two currents makes this a surprisingly pleasant getaway in the Arctic Circle.

A 2,000-year-old computer demonstrates remarkable engineering and astronomical precision.

On the side of a remote mountain, a stone face bearing an inscription of mysterious origin.