Underground civilization

History

The Mysterious Lost Underground Civilization of the Grand Canyon

Lying within the U.S. state of Arizona is one of the most majestic natural wonders of our planet, the Grand Canyon. Carved over hundreds of millions of years by the Colorado River and measuring 277 miles (446 km) long, up to 18 miles (29 km) wide, the Grand Canyon is a major natural phenomenon, but it is also a place…