A look back at the catastrophic May 18, 1980, eruption of Mount St. Helens in Washington—the most devastating volcanic eruption in U.S. history—and the events leading up to it.

On May 18, 1980, the Mount St. Helens became the largest and most destructive volcanic eruption in U.S. history. By the end of its cycle of fire and fury, 57 people had died.

When Mount Vesuvius erupted on August 24 in the year 79 A.D., it happened so quickly that the people of Pompeii and the surrounding areas had no time to escape. The volcano spewed out clouds of ash, burying terrified residents and preserving their last mo...