The Roman Forum of Thessaloniki is the ancient Roman-era forum of the city, located at the upper side of Aristotelous Square. It is a large two-terraced forum featuring two-storey stoas, dug up by accident in the 1960s. The forum complex also boasts two Roman baths, one of which has been excavated while the other is buried underneath the city, and a small theater which was also used for gladiatorial games. Although the initial complex was not built in Roman times, it was largely refurbished in the 2nd century. It is believed that the forum and the theater continued to be used until at least the 6th century.
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.