Vienna, Austria
1879
Vienna, Austria
1631
Salzburg, Austria
1594
Graz, Austria
1438-1462
Salzburg, Austria
1699
Salzburg, Austria
ca. 714 AD
Salzburg, Austria
1685-1696
Mondsee, Austria
748 AD
Altenburg, Austria
1144
Vienna, Austria
1898-1910
Klosterneuburg, Austria
1114
Linz, Austria
1862-1924
Zwettl, Austria
1137
Mariazell, Austria
1644-1683
Sankt Florian, Austria
1071
Heiligenkreuz, Austria
1133
Vienna, Austria
1698-1719
Krems an der Donau, Austria
1083
Feldkirch, Austria
13th century
Sankt Pölten, Austria
1621
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.