The people of the so-called red zone around the southern Italian port city of Pozzuoli, near Naples, have not slept well for a long time: for months, the earth in the Phlegrean Fields shook dozens of times a day – usually barely noticeable, but occasionally relatively violently, like three weeks ago. The reason: there is a supervolcano roaring beneath the “Campi Flegrei” – which means “burning fields” in German. Hot gases and water vapor are pushing the surface of the so-called caldera, the volcanic cauldron, higher and higher – now 15 millimeters per month, and the trend is increasing. This creates enormous stresses that are released in earthquakes. The floor has been raised by two meters in total since 2006. This is 20 centimeters more than during the last “critical situation” forty years ago.