At 68 square miles, Clear Lake boasts the title of California’s largest natural freshwater lake by surface area, a fact that surprises many visitors who assumed Lake Tahoe held that distinction.

While Southern Arizona is known for its porphyry copper deposits, Northern Arizona is better known for its nonmetallic commodities, including basalt, helium, potash and carbon dioxide (CO2). More than ...

Northern Arizona’s San Francisco Volcanic Field is a prominent geological landmark in the Southwest. Comprised of about 1,800 square miles, it is the location of more than 600 volcanic vents in the ...