MAP OF NATURE TRAILS IN MONTEFIASCONE (VT) The map is concerned with an extensive network of trails around 30 km long which develop inside a volcanic crater (fig. 1), whose products date back to about 155,000 years ago, part of the volcanic Vulsini volcano, in the province of Viterbo, Central Italy, whose alkaline magmatic activity began about 800,000 years ago. Along the paths there are historical and architectural landmarks and points of geological interest, as the lapillus old mine (fig. 2), cold mineral springs (fig. 3) and the numerous artesian wells (fig. 4).