Fort Gorazda was built by the Austro-Hungarian Empire near Kotor. The fortress's predecessor was built prior to the 1869 uprising. The current fort was built between 1884–86 and replaced an earlier structure; its most notable feature is a 100-ton Gruson rotating turret on its roof, the last remaining example of its type. The fort was used by the Austrians in artillery duels against Montenegrin batteries stationed on Mount Lovćen during the First World War. The Montenegrins were unable to destroy it and were pushed out of range in 1916 by an Austrian offensive. The damage to the fort was repaired and its guns were removed to support the Austrian field army. It was used as a depot by the Yugoslav Army until as recently as the early 1990s. It was subsequently abandoned and can be visited by the public.
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.