Castrojeriz, Spain
9th century AD
Fuensaldaña, Spain
13th century
Montemayor del Río, Spain
15th century
Vega de Valcarce, Spain
9th century AD
Vozmediano, Spain
14th century
Villafuerte, Spain
15th century
Curiel de Duero, Spain
7th century AD
Soria, Spain
12th century
Montealegre de Campos, Spain
12th century
Laguna de Negrillos, Spain
13th century
Bonilla de la Sierra, Spain
14th century
Ledesma, Spain
12th century
Olmillos de Sasamón, Spain
1446
Villalonso, Spain
15th century
Berlanga de Duero, Spain
15th century
Medinaceli, Spain
15th century
Trigueros del Valle, Spain
14th century
Topas, Spain
15th century
Castillejo de Robledo, Spain
12th century
Puente del Congosto, 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.