Grotte di Castro Potato Festival: a splendid gastronomic festival that aims to enhance one of the symbolic raw materials of this lakeside town. Potato production in the Viterbo area has always been one of the main agricultural activities carried out in Grotte di Castro. Every year at the turn of August, this PGI potato becomes the fulcrum around which dozens of recipes to taste revolve, but not only that, to accompany everything you will find live shows, music and much more.