Ayora, Spain
13th century
Fuentes de Valdepero, Spain
15th century
La Guardia, Spain
1664
Tudela, Spain
9th century AD
Coria, Spain
1st century AD
Segura de León, Spain
13th century
Haza, Spain
12th century
Peñaranda de Duero, Spain
15th century
Portillo, Spain
14th century
Alcalá de Guadaíra, Spain
11th century
San Saturnino, Spain
14th century
San Fernando, Spain
13th century
Ribadeo, Spain
17th century
Murcia, Spain
11th century
Chulilla, Spain
14th century
San Martín del Castañar, Spain
15th century
Vélez-Málaga, Spain
10th century AD
Castellón de la Plana, Spain
11th century
Morón de la Frontera, Spain
8th century AD
Puebla de Alcocer, Spain
12th 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.