San Gregorio Maggiore stands to the right of piazza Garibaldi which is one of the main entrances to the city. The church is Romanesque in style dating back to the eleventh century or the beginning of the twelfth. It has recently been restored and returned to its original appearance. The façade has two sloping roofs in which the huge bell towers dominates. The tower is contemporary with the church only in the lower parts. It was only finished in the fifteenth century. The façade has a three light mullioned window and three ogival niches in the upper part. A lovely portico leads through to a sixteenth century portal with three openings. To the left there is the fourteenth century Chapel of the Innocent with a fine sixteenth century baptismal font.

On the inside there is a nave and two aisles divided by columns and pillars previously used elsewhere. These in turn support Roman arches and end at the raised presbytery charactrised by three apses.

To the side of the presbytery there is the entrance to the crypt which has a nave and four side aisles. The crypt too has three apses.

The walls have fifteenth century frescoes of great interest.