The Neapolitans are attentive to the needles of Vesuvius, but this volcano is not the only geological danger that surrounds them, since some geoarchaeologists have put themselves to the other side, the caldera of the Campi Flegrei, and have discovered that the area has gone up and down three times since the 5th century.
The fossils of the marine living have come to this conclusion dated. It seems that the arrival of underground magma has several times raised the area of Campi Flegrei, while when the magma receded the land it sank and remained under the sea --if it is Pozzuoli -. In addition, most of the incidents occurred without eruption, since the writings have collected a single eruption, that of 1538.