A spiral staircase connects the limestone cave with Pembroke Castle, birthplace of King Henry VII.

This quiet park's strange sedimentary spires were named after Kodak's color film.

Sunset-colored dunes of volcanic ash make taking a poor photo impossible.

With nearly double the depth of the Grand Canyon, this Peruvian canyon is one of the deepest in the world.

It's hard to believe the dizzying patterns covering this abandoned mine are completely natural.

This narrow canyon has been carved by the river over thousands of years into spectacular and curious forms.

A little-visited waterfall in an otherworldly landscape.

Gnarled canopies of pink and purple wildflowers arch over the trail to the summit.

The highest tides in the world come in and out here twice a day, allowing you to essentially walk along the ocean floor.

This natural sea arch highlights Ireland's rugged coastal beauty.

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

In Northeastern Iceland lies something of an oxymoron: a steaming desert.

An ancient Scottish rock formation said to be the gravesite of a giant remains ensconced in legend and intrigue.

Each spring this woodland floor is carpeted with purplish flowers as far as the eye can see.

Islanders once used this dramatic, otherworldly landscape to hide their cattle from Viking raiders.

These hellish-looking cliffs in the Canadian Arctic have been burning for centuries.

The eerie remnants of an ancient forest were hidden under the sand for centuries.

Unknown to many, this sparkling turquoise lake hides amid Oregon's snowcapped mountains.

This unusual lava tube spouts seawater during high surf.

Nestled in the hills of Tuscany are gorgeous, multicolored hot springs.

The fifth-longest natural arch in the world, and the longest outside China.

Nestled within a German forest is an intriguing, growing rock.

Where the White Nile River dramatically cascades between Lake Kyoga and Lake Albert in Uganda.

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