I’m heading to the top of Mount Elbert, the tallest of all the Rocky Mountains. The Rocky Mountains, or Rockies for short, is a mountain range that stretches all the way from the USA into Canada.

From the back of a bush plane at Mission Field, the Crazy Mountains were only 20 miles in the distance, close enough for me to see late-afternoon shadows drift across their avalanche-scarred ridges.

Yellowstone has been the site of persistent volcanic activity for more than 2 million years. But what did the region look ...