In the first century A.D. Pompeii was a pretty and prosperous resort town. There were some 12,000year-round inhabitants and hundreds more who came down from Rome each summer to their villas by the sea. Ona hot summer day, around noon—it was August 24, A.D. 79—the people of Pompeii saw a huge cloud formingover the mountain north of the city. This was the last noontime Pompeii would ever know, because that cloud ofvolcanic debris was the beginning of a massive eruption that blew the top off Vesuvius, burying the city beneath 12 feet of rock and ash and unleashing a blast of toxic gases. Thousands were killed—in their homes, in thestreets, in businesses and brothels. Thousands more fled madly toward the sea. Those who were running for theirlives must have been surprised to see a curious figure racing not from but toward the volcano. This was the greatRoman naturalist Pliny the Elder. Seeing the initial eruption from a safe distance at his home near Naples, therenowned scientific observer just could not stay away. He grabbed his notebook and stylus and hightailed it forPompeii to gather firsthand information on this prodigious phenomenon. Pliny’s curiosity cost him his life.