The heart of the historic center is Piazza San Michele, on which the cathedral stands: structures from the eleventh century survive in the lower part of the façade and from the thirteenth century in the upper part. Its campanile, rebuilt in 1391-95 with five stories on a Romanesque base, is considered one of the finest late Gothic monuments in Liguria. The interior of the church, which has been restored to its medieval appearance, houses frescoes by Carrega, a panel painted by Pancalino in 1520 and a fifteenth-century Pentecost, in addition to the monumental nineteenth-century Serassi organ.