Yellowstone National Park is a popular destination for geology field trips. It’s easy to see why—the dynamic landscape ...

Some of us hiked through the surrounding forest and plateaus, discovering waterfalls and signs of wildlife: fresh moose tracks, bear scats, and the remains of reindeer killed by wolves.

In 1889, while searching for stray cattle in southwestern Colorado, rancher Richard Wetherill and his four younger brothers stumbled across ancient ruins in the cliffs of a high plateau known as ...