The Holy chamber of Oviedo (Cámara Santa de Oviedo) is a pre-Romanesque church built next to pre-romanesque Tower of San Miguel of the city's cathedral. Nowadays, the church occupies the angle between the south arm of the cathedral transept and a side of the cloister.
It was built during the 9th century as a palace chapel for King Alfonso II of Asturias and the church of San Salvador of Oviedo. Apart from acting as royal chapel, the Holy Chamber was built to house the jewels and relics of the cathedral of San Salvador in Oviedo, a function it continues to have 1200 years later. Some of these jewels were donated by the Kings Alfonso II and Alfonso III, and represent extraordinary gold artifacts of Asturian Pre-Romanesque, brought from Toledo after the fall of the Visigothic kingdom.
Consequently, the cathedral of Oviedo was also called Sancta Ovetensis; owing to quantity and quality of relics contained in the Cámara Santa. The Holy Chamber remains as the only sample of the early medieval complex. It was built as a relics' room to keep the different treasures associated with the Kingdom of Asturias (Cross of the Angels, Victory Cross, Agate box, Arca Santa and Sudarium of Oviedo), brought from Jerusalem to Africa, and after several translations was finally deposited at Oviedo by Alfonso II of Asturias.
It was declared a World Heritage Site by UNESCO in December 1998.
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.