Geras, Austria
1153
Krems an der Donau, Austria
1014
Eisenstadt, Austria
13th century
Admont, Austria
1074
Gurk, Austria
1140-1200
Innsbruck, Austria
1751
Millstatt, Austria
1070
Seitenstetten, Austria
1112
Hall in Tirol, Austria
1567
Wernberg, Austria
13th century
Neuberg an der Mürz, Austria
1327
Eisenstadt, Austria
1715
Graz, Austria
1881-1887
Mauerbach, Austria
1314
Ossiach, Austria
1024
Lienz, Austria
1349
Stams, Austria
1273
Sankt Lambrecht, Austria
1076
Leoben, Austria
1004
Reutte, Austria
1628
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.