At 78, Eladia Mejia is no little old lady in a rocking chair. She is stout, straight-backed, witty and indomitable, and her passion is teaching mestizo peasant children in the bandit-infested mountains of western Colombia. Since this requires schools, she builds them—partly with her own hands. Her record: 129 schools, plus four hospitals and a half-completed orphanage that will cover four city blocks when it is finished. "I am no architect," says she. "But I have the lines of four walls in my head, and with that I do a devil of a lot."
Despair. Last week, on the first vacation of...