Łańcut, Poland
1761
Łódź, Poland
1901
Zamość, Poland
1696
Olsztyn, Poland
1380-1445
Trzebnica, Poland
1203
Frombork, Poland
1329-1388
Krosno, Poland
1647
Kalwaria Zebrzydowska, Poland
1600
Pelplin, Poland
1258
Cieszyn, Poland
c. 1180
Koszalin, Poland
1300-1333
Świdnica, Poland
1656-1657
Brzeg, Poland
1368
Nysa, Poland
1195/1392
Lubiąż, Poland
1175
Gniezno, Poland
11th century
Bydgoszcz, Poland
1582-1602
Chełmno, Poland
1280
Brzeg, Poland
14th century
Supraśl, Poland
1498
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.