Same Situation, Far Apart: Satisfying Work In Nice, France (left), two paleontologists examine a skull bone, and in Arizona, the United States (right), a woman said to be over 100 years old prepares wool for weaving. Note their facial expressions: Elders are often happier when they continue working.
SEBASTIEN NOGIER/AFP/GETTY IMAGES
© RICHARD NOWITZ/NATIONAL GEOGRAPHIC SOCIETY/CORBIS