A unique rock formation that only a few have managed to venture inside.

The spherical grains of white quartz sand give every step on this Australian beach a distinctive sound.

The massive mountain ash that once stood at this site was cut down in an effort to prove that it was, indeed, the tallest of its kind.

A waterfall rushing through a lush fern gully in Australia's Tarra-Bulga National Park.

Australian Lake set aglow by Noctiluca Scintillans.

Once a welcome symbol for maritime travelers entering Edrom.

This tree, with its large oval-shaped scar, is a rare piece of Aboriginal cultural history.

These sea cliffs are an epic natural wonder.

An abandoned railroad tunnel is now filled with bioluminescent bugs.

A giant Australian fruit and tropical farm.

The ruins of Brisbane’s own Alcatraz now sit in the middle of a national park.

Beauty and history abound in this remote West Texas canyon.

A spring-fed pool so deep it's used for scuba diving as well as swimming.

A group of college students hauled a desk up a mountain more than 40 years ago. The notebooks inside have become a makeshift time capsule.

Legacy of the earthquake that nearly wiped Lisbon off the face of the Earth.

An important Mayan religious and trading center dating back to 200 BC.

Sparkling, calcite-covered skeletons of children who may have been sacrificed to appease an angry god.

A monument to the center of the North American continent may be off by a few miles.

The world's tallest turtle riding the world's largest snowmobile.

A rim-made reptile in North Dakota.

A sign marks the plane crash that caused two nuclear bombs to fall in North Carolina.

Like Mars, but much closer.

An eerie and beautiful group of columns mark the site of a grand mansion lost to time and fire.

Alabama has a fiberglass Stonehenge. With apologies to Spinal Tap, this one is full-size.