Slava R.
Google
Actually, we wanted to go see Criptoportico forense, but we entered the cathedral instead, and so we discovered a series of hidden treasures: the little museum at the back (with beautiful carved wooden panels), the early Christian church located beneath the floor, the Ottonian frescoes from the 11th century that are now above the ceiling, and a cloister with unusual round/hexagonal columns. All of this was accompanied by the narration of the very kind, knowledgeable and enthusiastic guide of the Cathedral museum (Matteo Del Col). Highly recommended, especially the frescoes! It seems that few people are aware of their existence. It's just a few euros for a 1h+ excursion.