A thin band of smoke rises from the cone of Mt. Vesuvius, a subtle warning that this supervolcano is still very much alive. A few miles down the flanks in the ancient ruins of Pompeii, a group of 55 experts wearing white hazmat suits and yellow hard hats tap at what’s left of the buildings in this once vibrant city.

They are installing sensors that will measure a number of indicators, from humidity in the stone walls to vibrations from the volcano's seismic activity and nearby highway system, and beam data to a research team in nearby Salerno.