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 Walls of Constantinople are a series of defensive stone walls that have surrounded and protected the city of Constantinople (today Istanbul) since its founding as the new capital of the Roman Empire by Constantine the Great. With numerous additions and modifications during their history, they were the last great fortification system of antiquity, and one of the most complex and elaborate systems ever built. They were also the largest and strongest fortification in both the ancient and medieval world.
Initially built by Constantine the Great, the walls surrounded the new city on all sides, protecting it against attack from both sea and land. As the city grew, the famous double line of the Theodosian Walls was built in the 5th century. Although the other sections of the walls were less elaborate, they were, when well-manned, almost impregnable for any medieval besieger.