The castillo de Santa Ana, also known as Castillo de Las Roquetas, is a fortification built between the 16th and 17th centuries, located in the town of Roquetas de Mar which was used for refugee to the inhabitants who lived near the port. It has an oblong shape. Near the castle there is a lighthouse.
The 1804 earthquake destroyed most of the structure, and only survived one of the towers and the raised level area, which has been conserved and recovered.
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.