At an elevation of 438 meters on the Cresta del Gallo Sierra, Castillo de La Luz is an 9th century construction built by the Moors. The castle was part of Murcia's defense buildings and a check point between the coast and the city. A tank, and parts of a wall and a tower, still stand. It was abandoned in the 13th century after Murcia was merged to the kingdom of Castilia.
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.