The Hajji Ahmed the Ducat Minter's Mosque is one of the most easily recognizable architectural symbols of Livno, Bosnia and Herzegovina. Built in 1574 (some date to 1587), it is situated on a hill overlooking old town of livno, the river Bistrica and the spring Duman in the upper section of the old town of Livno. The mosque complex consists of compact main building of the mosque under a dome and uncharacteristically short minaret, with a clock tower which was erected some 100 years later, between 1670 and 1680. but more likely in 1659. It is still in function today, and finally within perimeter is almost 500 years old necropolis with characteristic early Bosnian Muslim tombstones and later ones.
References: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.