Vorau, Austria
1163
Kremsmünster, Austria
777 AD
Graz, Austria
1714-1724
Herzogenburg, Austria
1112
Bregenz, Austria
1737
Pernegg, Austria
1153
Klagenfurt, Austria
1142
Lambach, Austria
1040
Seckau, Austria
1143
Gaming, Austria
1330
Rein, Austria
1129
Wiener Neustadt, Austria
1440
Engelszell, Austria
1293
Vomp, Austria
1138
Reichersberg, Austria
1084
Wilhering, Austria
1146
Sankt Georgen am Längsee, Austria
1002-1008
Lilienfeld, Austria
1202
Dorfbeuern, Austria
8th century
Frauenkirchen, Austria
1695
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.