Solfatara is a shallow volcanic crater at Pozzuoli near Naples which is part of the Campi Flegrei volcanic area. It is a dormant volcano which still emits sulfurous fumes. The name comes from the Latin term Sulpha terra, “land of sulfur”, or “sulfur earth”. It was formed around 4000 years ago and last erupted in 1198 with what was probably an explosive steam-driven eruption, caused when groundwater interacts with magma. It has many fumaroles (a smoke-opening in the planet’s crust which emits steam and gases) and mud pools. The area is well known for its bradyseism and the vapours have been used for medical purposes since Roman times.