Íscar, Spain
13th century
Alcalá de Guadaíra, Spain
11th century
Hondarribia, Spain
1890
Belalcázar, Spain
15th century
Lorca, Spain
10th century AD
Villaviciosa, Spain
15th century
Lugo, Spain
15th century
Belmez, Spain
13th century
Bujalance, Spain
10th century AD
Friol, Spain
16th century
Torredelcampo, Spain
12th century
Merindad de Río Ubierna, Spain
14th century
Villanueva de la Cañada, Spain
14th century
Sanlúcar de Guadiana, Spain
c. 1642
Espera, Spain
914 AD
Laquidáin, Spain
12th century
Sandiás, Spain
12th century
Urbel del Castillo, Spain
15th century
Batres, Spain
15th century
Alija del Infantado, Spain
15th century
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.