Geology

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.

This canyon is named for a unique geologic formation where the river vanishes underground near the mouth of the canyon and reappears farther down.

The now-serene site of the largest earthquake ever recorded in North America.

A geothermal paradise with bubbling mud pools and bright blue hot springs.

See 150 million-year-old dinosaur tracks and bones dating back to the Jurassic period.

Once one of the most polluted caves in America, now an environmental success story and a museum dedicated to caves.

Red rock "fangs" jut out of the desert near the Extraterrestrial Highway.

The walls of the statehouse tell the story of Ohio’s prehistoric past.