February 20, 1943, began as an average day on Dionisio Pulido's farm in rural Mexico. But the afternoon in his fields near the small village of Paricutín was anything but ordinary. Dionisio was burning brush while a hired laborer, Demetrio Toral, plowed. Demetrio had just finished a furrow and began turning the plow when he saw an extraordinary sight: A huge fissure (hole) had opened up almost exactly in the furrow he had just plowed. Dionisio also saw the gaping hole in his fields. Later, he described the scene: The ground swelled and raised itself 2 or 2 1/2 meters high,and a kind of smoke or fine dust-gray,like ashes-began to rise up in a portion of the crack. . . . Immediately more smoke began to rise, with a hiss or whistle, loud and continuous, and there was a smell of sulfur. . . . I ran to see if I...