Descend the Andes Mountains to agricultural civilizations where locals use a spring for power.
Follow host David Yetman and his brother, geologist Dick Yetman, as they descend from 10,000 feet in the Andes Mountains into the heart of the Amazon Desert. Travel by 4x4 down a treacherous one way road through a cloud covered forest. This area hosts hillside agricultural civilizations that continue to harvest the land much as their ancestors have done for hundreds of years. As they continue to the bottom of a canyon deeper than the Grand Canyon, they cross one of the rivers that helps form the Amazon, the Rio Maranon, noting the growing abundance of desert vegetation. Also in this episode, hydrology meets the desert as the brothers encounter entrepreneurial locals using a gushing spring at the base of the mountains to power woodworking machinery.