The remains of a magnificent medieval fortress that was the capital of a vast empire.

The world of the ancient Celtic civilization explained through a bewitching 11 acre garden.

A moody and picturesque riverside ruin overgrown with vegetation.

It might not be as impossible to reach as its name would imply, but just about.

A collision of human error and natural geothermal pressure created this rainbow-colored geologic wonder.

This quirky little private museum is home to more than a thousand stones, carved by nature, that resemble human faces.

Volcanic rocks ground down into sand make this Spanish beach as black as night.

A boardwalk winds through this sliver of coastal nature hidden within Sydney.

A chain of 16 wondrous lakes formed as a result of the gradual dissolution of soluble layers of bedrock.

Rainbow-hued in the summer and crystalline in the winter, this salty lake has inspired battles, temples, and plenty of awe.

The world's brightest bioluminescent bay.

Rusting, graffiti-covered tanks litter the beach of this island, once used by the U.S. military for target practice.

An abandoned hotel in the highlands of Bali is shrouded in stories of ghosts, curses, and corruption.

A historic observatory precariously perched at the "Top of Europe."

A lonely beacon, precariously perched atop a remote sliver of rock.

Double spiral staircases are not unheard of, but they are very rare.

This eccentrically decorated palace is replete with grottoes, fountains, tunnels, and caves.

This rusting remnant of the local herring industry is being given a second life.

Three million year old fossils are exposed for all to see on this Icelandic shore.

This volcanic cave lake is essentially hard proof that Iceland is the most magical place on Earth.

This oceanside Reykjavik spot is speckled with recycled sculptures and large stones.

The bright red stripes streaking across the rocks are the star feature at this Icelandic waterfall.

Climbing Iceland's highest peak on the rim of the Oræfajökull volcano.

Surrounded by ash fields in Iceland, an impossibly verdant valley looks like something out of a fairytale.