Basilica di San Pietro
Saint Peter's Basilica is the old cathedral of Acqui Terme and one of the oldest in Italy. It was built within the boundary of an early Christian cemetery in the 4th century and in the first decades of the 11th century it was rebuilt in Romanesque style; later it was employed as a Benedictine abbey, before being abandoned and then restored to worship in the 18th century and dedicated to Maria Addolorata. The exterior of the church is essentially primitive in style. The facade and the missing parts were rebuilt during restoration work carried out between the 30s and the 50s by the architect Vittorio Mesturino. Of the early medieval construction, the central apse remains as do the smaller polygonal apses and the upper exterior sides of the main nave; the octagonal bell tower was added later. The interior, divided into three naves by octagonal pillars, is extremely simple and austere, with a whitewashing that to date does not leave visible traces of the frescos on the walls.