The National Archaeological Museum, in the centre of Sofia, occupies the building of the largest and oldest former Ottoman mosque in the city, originally known as Koca Mahmut Paşa Camii. The construction started in 1451 under grand vizier Veli Mahmud Pasha but due to his death in 1474 the mosque has been completed in 1494. The museum was established as a separate entity in 1893 as the National Museum directed by Czech Václav Dobruský with its headquarters in the former mosque that previously housed the National Library between 1880 and 1893.
Prehistory Hall displays a collection of items dating from between 1,600,000 BC and 1,600 BC. The collection is chronologically displayed and includes various findings from caves around Bulgaria, tools of the earliest humans who inhabited its modern territory, drawings, simple pottery, ritual items and many others.
Treasury displays grave inventory and other treasures from the late Bronze Age to late Antiquity. Two of the most well-known Bulgarian treasures are located here: the Valchitran and Lukovit Treasures. Main Hall hosts a collection of diverse items ranging from ancient Thrace, Greece and Rome to the late Middle Ages.
The medieval Section includes a gallery of medieval books, woodwork, drawings, metal objects and other items characteristic of the era.
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.