Adria Cathedral (Duomo di Adria) replaced the much older former cathedral nearby, dedicated to Saint John, which continues in use as a parish church. The new cathedral, dedicated to Saints Peter and Paul, was built in the early 19th century over a 14th-century church. When works were undertaken in 1830 to investigate the stability of the foundations, a Byzantine crypt and frescoes were discovered.
The cathedral also contains a Byzantine bas relief of the 6th century, a Byzantine altar and crucifix, and in the sacristy some magnificently carved cupboards by Jacopo Piazzetta from the Charity School of Venice.
Behind the building a replica of the Grotto of Lourdes was constructed in the 1930s, which still attracts many visitors.
References:The Church of St Donatus name refers to Donatus of Zadar, who began construction on this church in the 9th century and ended it on the northeastern part of the Roman forum. It is the largest Pre-Romanesque building in Croatia.
The beginning of the building of the church was placed to the second half of the 8th century, and it is supposed to have been completed in the 9th century. The Zadar bishop and diplomat Donat (8th and 9th centuries) is credited with the building of the church. He led the representations of the Dalmatian cities to Constantinople and Charles the Great, which is why this church bears slight resemblance to Charlemagne's court chapels, especially the one in Aachen, and also to the Basilica of San Vitale in Ravenna. It belongs to the Pre-Romanesque architectural period.
The circular church, formerly domed, is 27 m high and is characterised by simplicity and technical primitivism.