Istanbul explores a city which stands as a gateway between the east and west, one of the indisputably greatest cities in the world. Previously known by the names Byzantium and Constantinople, this is the most celebrated metropolis in the world to sit on two continents, straddling the dividing line of the Bosphorus Strait between Europe and Asia. During its long history, Istanbul has served as the capital of the Roman, Byzantine, Latin and Ottoman Empires. Its architecture reflects these many cultures, including the Hagia Sophia (Byzantine), the Blue Mosque (Ottoman), the Valens Aqueduct (Roman), the Topkapi Palace (Ottoman), and more modern Art Nouveau avenues built in the 19th and 20th centuries - many of which are UNESCO World Heritage sites. sakriti opis