Kyustendil, Bulgaria
14th century
Varna, Bulgaria
12th century
Ruse, Bulgaria
15th century
Veliko Tarnovo, Bulgaria
11th century
Gabrovo, Bulgaria
12th century
Mezdra, Bulgaria
16th century
Sofia, Bulgaria
1345
Sofia, Bulgaria
1493
Gabrovo, Bulgaria
1833
Varshets, Bulgaria
1240/1869
Chiprovtsi, Bulgaria
10th century AD
Montana, Bulgaria
1850-1853
Sofia, Bulgaria
13th century
Veliko Tarnovo, Bulgaria
17th century
Veliko Tarnovo, Bulgaria
1846
Vidin, Bulgaria
14th century
Strupets, Bulgaria
14th 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.