Rocca, a medieval castle with quadrangular bastions bounded by a canal with drawbridge, was built in 1124. It was the fortress of the noble family Scaligeri, who became the Lords of Verona. It was rebuilt several times and it was used by the Austrians as barracks in the 18th century. It is frequently the seat of cultural activities, especially during the summer months. It hosts the Civic Museum and of the Picture Gallery.
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.