Geology

This cave at the base of an unusually shaped cliff is said to be inhabited by a mythical forest enchantres from Scandinavian folklore.

The second largest monolith in the world was once betrayed by its lover, Ben Aicha.

You can dig up your own crystals in the quartz capital of the world.

Construction uncovered this trove of fossils, which visitors are welcome to add to their own collections.

A life-sized recreation of the megafauna that once roamed this region is a feature at the birthplace of American paleontology.

A boulder so big and tough, they had to turn it into a landmark.

A Native American petroglyph, the site of an emigrants' waystation, and the ruins of an early 20th-century sheep camp are all found at this crossroads.

A volcanic crater that visitors can look inside.

The spectacular geological formations make it one of the most impressive caves in Europe.

An immense cave that has served as an outlaw's treasure trove, an underground dance hall, a nuclear fallout shelter, and much more.

This prehistoric karst cave is situated near a working ranch and historic warm springs.

This open-pit mine is now an abandoned symbol of Bisbee's copper-mining heritage.

At the western edge of Palm Springs, a rugged desert canyon trail leads to a waterfall at the base of the San Jacinto Mountains.

This steep-walled ravine contains animal-shaped formations made from sandstone.