The Cathedral of Ratzeburg, one of the oldest brick churches of Northern Germany, is a basilica with three naves. Its arches are supported by pillars and it is built in the form of a cross with a choir quadrangle and a halfround apse. The last restoration (completed in 1966) returned the cathedral to its late Romanesque conception, so you can discover most of the unity and integrity of its original design.
The cathedral was founded in 1154, when Henry the Lion, Duke of Saxony, and Hartwich I, Archbishop of Hamburg, refounded the episcopal seat of Ratzeburg, and Evermodus became its first bishop. The cathedral was restored, and additions were made to it in the 15th century.
The Cloister, on the north side of the Cathedral, was begun shortly after the completion of the Cathedral (ca. 1220). The cloistered courtyard is open for the public.
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.