Bonilla de la Sierra castle has three wall sections and three turrets of different styles and origins. The main par of the castle was formed by the Tower of Homage, of the 14th century, it has matacanes and round arches, and under the tower is the main yard and the rooms. The castle contains 14th-century paintings.
It was the resting place of the prelates of the Ávila bishopric, and held important episcopal synods, as the one in 1384. Bishop Sancho Dávila had a wall built around the village in the 14th century.
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.