Extras
Use real data to design your own virtual renewable energy power systems.
Try classifying clouds and investigating the role they play in severe tropical storms.
Alaska’s Mendenhall Glacier—a 13-mile-long expanse—thousands of feet thick.
In Mesa Verde National Park, I’ve come to see a genuine wonder of the ancient world.
25 miles from Santa Barbara lie the remote and windswept Channel Islands.
More than 13,000 years ago puts these bones during the last ice age.
A giant cauldron of magma simmering beneath Yellowstone is threatening to blow.
Two scientists scan islands off Panama for clues to determine how the country was formed.
Fly coast to coast to see highlights of how North America took the shape it is today.
These hollowed-out rocks help explain why North America’s giant inland sea disappeared.