Pompeii is one of the most mysterious places on the planet, and just next door, the remains of a second abandoned Roman town, Herculaneum, pose new questions about what happened when Mount Vesuvius erupted; cutting-edge tech might have answers. This is a mashup of S04E03 "Pompeii's Doomsday Mummies" and S06E02 "Vesuvius's Secret Victim" (Herculaneum).