The facility, called Diamond Light Source, is one of the most powerful and sophisticated X-ray facilities in the world, used to probe everything from viruses to jet engines. On this summer afternoon, though, its epic beam will focus on a tiny crumb of papyrus that has already survived one of the most destructive forces on the planet—and 2,000 years of history. It comes from a scroll found in Herculaneum, an ancient Roman resort on the Bay of Naples, Italy, that was buried by the eruption of Mount Vesuvius in A.D. 79. In the 18th century, workmen employed by King Charles III of Spain, then in charge of much of southern Italy, discovered the remains of a magnificent villa, thought to have belonged to Lucius Calpurnius Piso Caesoninus (known as Piso), a wealthy statesman and the father-in-law of Julius Caesar. The luxurious residence had elaborate gardens surrounded by colonnaded walkways and was filled with beautiful mosaics, frescoes and sculptures. And, in what was to become one of the most frustrating archaeological discoveries ever, the workmen also found approximately 2,000 papyrus scrolls.