Castillo de Tabernas is a ruined castle on the outskirts of the municipality of Tabernas. It was built in the 11th century during the time of Arab domination. It is of Moorish style and is situated on top of a hill. When it was built, it occupied the entire hill, though currently only a part is preserved. During the siege of Almeria, Ferdinand and Isabella ensconced themselves in the castle.
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.