Strabo called the Solfatara the "Forum Vucalni", home of the God Vulcan, antechamber of the Underworld. Its smell has always been unmistakable, the fumes reach the sky, the mud bubbling in the cauldrons, and the hot gases spray out of the rocks. It is one of the more than 40 active volcanoes that make up the Phlegraean Fields, a naturalistic oasis of geological, botanical and faunal rarities.
The elliptical crater extends for 33 hectares of surface and looks like an expanse of warm earth interrupted by small lakes of boiling mud. These release strong exhalations which, at the same time, represent a fundamental relief valve for the gases that exert pressure from the subsoil. This aspect, together with other phenomena called "secondary volcanism" such as mofetes (CO2 exhalations), fumaroles (water vapor emissions), and mud volcanoes, is to be attributed to the quiescent phase of the volcano, which the same term " solfatara” indicates.
From the Bocca Grande, the main fumarole of the Solfatara, vapors that reach 160 ° C come out. Its fumes, with a characteristic odor, are deposited on the surrounding rocks giving it a yellow-reddish color. Of great interest are the mud pit, the mineral water well and the old stoves, real natural saunas.
Its particular conformation, the atmosphere it recreates, contributes to making the Solfatara a place of great charm.