The Aragonese Alfonsino Castle, best known as Forte a Mare ('Sea Fort'), was built by King Ferdinand I of Naples in 1491 on the S. Andrea island facing the port of Brindisi. It is divided into two sections: the 'Red Castle' (from the color of its bricks) and the more recent Fort.
The castle was besieged by Venetians in 1529 and French army in 1799. It was damaged by storm in the modern age and was abandoned in 1984.
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.