One team member, Dr. David L. Featherman, a social psychologist who recently became president of the Social Science Research Council in New York, said: "We wondered if we were identifying a new life period on the horizon called midlife.

The Inca Trail ends after its final descent from the notch in the horizon called Intipunku (Sun Gate).

But there's an even faster standard on the horizon, called Light Peak.

The bleached soil goes over into a red or redbrown horizon called rusty soil.