Montefiascone Cathedral or the Basilica of Santa Margherita is a former Roman Catholic cathedral in Montefiascone in the province of Viterbo, Italy, dedicated to Saint Margaret of Antioch, the patron saint of the town. It was formerly the episcopal seat of the Diocese of Montefiascone and is now a basilica minor.
It is one of the most important churches in the area, and has one of the largest domes in Italy, which is visible from most of the towns of the Viterbo area.
Wikipedia https://en.wikipedia.org/wiki/Montefiascone_Cathedral
Coordinates 42°32'11.253" N 12°1'49.865" E