Campoli Appennino is laid out in a semicircle along the northern rim of a great elliptical sinkhole, which here they call the Tomolo, at six hundred and fifty metres. The name comes from campora, the word for the arable land up at altitude, between the mountain valleys: which is exactly this. The village lies between the Liri valley and the Valle di Comino, inside the national park of Abruzzo, Lazio and Molise, and below it runs the Lacerno. In the Middle Ages, when the great d'Aquino estate was taking shape, Landolfo I d'Aquino, first lord of the Castello Cantelmo, received the lands of Albitum, Campoli, Settefrati and part of Aquino; between the end of the thirteen hundreds and the beginning of the fifteen hundreds Campoli followed the fortunes of the county of Alvito, a fief of the Kingdom of Naples in the giustizierato of Terra di Lavoro. From that time there remain a medieval tower twenty-five metres high, which is the thing people come to see, and a stretch of walls; at the place called Largo dell'Acqua there is what they call Nero's aqueduct; and the church of San Pancrazio Martire was built in 1594.
But the thing the village now lives around is the hole. Inside the great karst doline, over more than fifteen hectares of ground, is the wildlife area of the Marsican brown bear, made jointly by the comune and the national park and opened in 2010: five bears live there in semi-liberty, free to move without hindrance in an environment like the natural one, behind a fence that visitors can walk up to. In 2017 a Bear Centre was opened in the village too, with a multimedia display devoted to the animal. The bear is in the calendar as well: every August they run the Corsa dell'Orso, a ten-kilometre road race. The other thing Campoli is known for is underground rather than inside the hole: the white and black truffle, recognised among the traditional agri-food products of Lazio, which has its national fair on the second and third weekends of November.