The Etruscan hilltop town of Pitigliano in southern Tuscany lies within the Vulsini District, an area of multi-centre volcanic complexes covering over 2200 square-km, (1400 square-miles), most active from 600,000 to 150,000 years ago, even if volcanic activity was recorded as recently as the 1st century bc and some speculate the complex is still active. The largest and most obvious vestige of volcanism is Lake Bolsena, Europe’s largest, roughly circular volcanic lake known to the Romans as <Lacus Volsiniensis> just over the border in Lazio.
Ash from multiple eruptions settled in the surrounding arc from Orvieto to Montefiascone and Pitigliano, eventually compacting and cementing into the hard tuffaceous rock called the Pitigliano Formation. The town of Pitigliano floats atop a ridge of this volcanic tuff, the foundations of its medieval houses carved quite literally into the bedrock, and vines, too, dig their roots into it. While wine quality has been modest in recent times, there are signs the region is re-awakening, led by such producers as Sassotondo.