Canosa 'castle' is actually the acropolis of ancient Castrum Canus. The three great towers are the ruins of the eponymous estate located atop the hill overlooking the valley Ofantina. Originally a place of worship and pre-Roman fort, built of tufa blocks was rebuilt as a bastion of the same materials by the Grimaldi. Last owners, from 1856, were the Prince of Canosa Capece Minutolo of Naples, and remained until 1948. The wear of the blocks that compose it and the color denotes the passage of these various civilizations that have developed the structure in different epochs. The castle has also reported damage after the devastating bombing of the Second World War. Along the steep hill of the Acropolis, there is the old part of the country, with its narrow streets and staircases. At the southern base lie the remains of a Roman amphitheater.
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.