Begun in the 16th century by Hernando de Vega over remains of a 10th century castle, the Grajal de Campos Castle was finished by his son Juan de Vega y Acuna, count of Grajal. Designed to withstand the use of artillery the castle has sloped walls and its overall height is lower than those of earlier castles, making it difficult and hard to target by cannon fire.
The Grajal de Campos Castle has a square plan with four corner towers covering all blind spots and it is located on the western edge of the village over a small hill. In this same village there is a renaissance palace owned by the same counts which is said to be linked by an underground tunnel with the castle.
To this day, the castle belongs to the actual Duke of Alburquerque, its interior is dismantled and can be visited.
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.