Vienna, Austria
1359
Salzburg, Austria
774 AD
Vienna, Austria
1327
Vienna, Austria
1701-1733
Salzburg, Austria
1208
Salzburg, Austria
696 AD
Salzburg, Austria
1694-1707
Vienna, Austria
1276
Vienna, Austria
1599-1632
Innsbruck, Austria
1717-1724
Vienna, Austria
1716-1737
Vienna, Austria
15th century
Innsbruck, Austria
1553
Salzburg, Austria
1694-1702
Linz, Austria
1669-1683
Graz, Austria
13th century
Melk, Austria
1089
Vienna, Austria
c. 800 AD
Vienna, Austria
1858
Vienna, Austria
1160
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.