The Byzantine and Christian Museum was founded in 1914, and houses more than 25,000 exhibits with rare collections of pictures, scriptures, frescoes, pottery, fabrics, manuscripts, and copies of artifacts from the 3rd century AD to the late medieval era. It is one of the most important museums in the world in Byzantine Art. In June 2004, in time for its 90th anniversary and the 2004 Athens Olympics, the museum reopened to the public after an extensive renovation and the addition of another wing.
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.