Fortress of Justinian or simply known as Tirana Castle dates is a remnant from the Byzantine-era. The preserved ruins show that the castle was probably founded in antiquity, maybe in the Early Byzantinum (400-600 AD). The fortress is the place where the main east-west and north-south roads crossed, and formed the heart of Tirana. The current fortification has three known towers and it is undergoing a process of restoration, for touristic purposes. Inside the fortified walls of the former fortress, there are many buildings that can be visited, including restaurants, hotels, and cultural institutions.
About all that is left of the fortress above ground is a 6-metre high Ottoman-era wall, covered in vines. The recently uncovered wall foundations were incorporated into the pedestrianised Murat Toptani Street, while a mosaic commemorating the 100th Anniversary of Albania's Independence was unveiled near the Albanian Parliament.
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.