Zamora Castle features Pre-Roman foundations and a Romanesque general structure. It was built between the 10th and 12th centuries. According to the chronicles it was ordered to be built by Alfonso II of Asturias, although it would probably be done by Ferdinand I of León (in reign 1056–1065). The castle stands northwest of the Cathedral, with magnificent views of the town and the river from the keep.
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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.