Geology

These stark white cliffs were spat up by the sea and are slowly being retaken by it.

In the St. Francois Mountains in the Ozarks at 1,772 feet above sea level, Taum Sauk Mountain is the highest (and possibly oldest) peak in Missouri.

One of the Eight Wonders of Kansas and the first official National Natural Monument these stark formations look like nature's Stonehenge.

The bones of this aquatic dinosaur turned to opal over the centuries and the beast's remains were almost sold as jewelry.

The second-largest ceremonial mound in the United States is an artificial hill that is loosely shaped like a pentagon.

An Icelandic island full of diving birds and legend.

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

This elderly couple's hand-picked collection of rare gems is one of the finest in all of Iceland.

This Taiwanese promontory is covered in otherworldly hoodoo formations.

This stream-carved gorge has inspired poets, hidden smugglers, and trained soldiers, all without losing its beauty.

This dormant volcanic crater has been converted from a roiling pit of magma to a pleasant hiking spot.

This neolithic stone grave has been altered and restored so often its now more neo than lithic.

This trio of Australian rock spires may have inspired aboriginal legend or just modern tourism.

This massive water spout has been luring visitors for hundreds of years, some to their death.

A mysterious stone embedded at the base of a historic Boston building.

A rocky Irish outcropping with a history of wealth, conflict, and ruin.

A natural arch carved by a river gave its name to the so-called "Cave of Forgotten Dreams."