Istanbul City Walls
The Istanbul City Walls are fortifications that were built during 413-477 by the Byzantine Emperor Thedosius II. They stretch for 6-7 km, starting from the Marble Tower on the Marmara shore and ending at the Golden Horn. The Yedikule Walls were constructed by Fatih Sultan Mehmed the Conqueror between 1457-1458. The fortifications feature 16 gates and consist of three defensive layers: the inner walls, outer walls, and a trench. The inner walls measure 3-4m in thickness and reach a height of 13m, while the outer walls, located 15m away, are 2m thick and 10m high. A trench is positioned in front of the outer walls. The restoration of the Istanbul city walls is underway as part of the UNESCO protection programme.