Farming in the world's driest desert.

• Position: Anthropology - Atacama Desert, Chile

High in the Atacama Desert, around 10,000 feet, you can look at the fields around Turi, Chile, and see small neatly laid out fields, terraced and lined with rocks. No crops are growing there now, but it looks as though the farmers laid down their stone hoes and just walked away. Frances Hayashida, associate professor of anthropology at the University of New Mexico, Albuquerque, says that is more or less what they did more than 500 years ago. The climate is so dry the fields and the elaborate irrigation systems are almost perfectly preserved.

"These are systems that were developed about 1000 A.D. when people figured out how to divert water from springs that are recharged by snowmelt from the Andes." There was not much water even then, however. Anthropologists have not yet tried to calculate exactly how much farmers had to work with, but farming always was marginal here.

It was conquest, first by the Incas, then by the Spanish, that changed the lifestyles of the indigenous people and made copper mining into a local industry. The Incas conquered this land in the early 1400s.

"We think they brought in workers to work in the mines. They put in an extensive road system to...