With its strategic location on the Bosphorus peninsula between the Balkans and Anatolia, the Black Sea and the Mediterranean, Istanbul has been associated with major political, religious and artistic events for more than 2,000 years. Its masterpieces include the ancient Hippodrome of Constantine, the 6th-century Hagia Sophia and the 16th-century Süleymaniye Mosque, all now under threat from population pressure, industrial pollution and uncontrolled urbanization.

Brief synthesis Strategically located on the Bosphorus peninsula between the Balkans and Anatolia, the Black Sea and the Mediterranean, Istanbul was successively the capital of the Eastern Roman Empire, and the Ottoman Empire and has been associated with major events in political history, religious history and art history for more than 2,000 years. The city is situated on a peninsula which is surrounded by the Golden Horn (Haliç), a natural harbor on the north, the Bosphorus on the east and the Marmara Sea on the south. The Historic Peninsula, on which the former Byzantium and Constantinople developed, was surrounded by ancient walls, built initially by Theodosius in the early fifth century. The Outstanding Universal Value of Istanbul resides in its unique integration of architectural masterpieces that reflect the meeting of Europe and Asia over many centuries, and in its incomparable skyline formed by the creative genius of Byzantine and Ottoman architects. The distinctive and characteristic skyline of Istanbul was built up over many centuries and encompasses the Hagia Sophia whose vast dome reflects the architectural and decorative expertise of the 6th century, the 15th century Fatih complex and Topkapi Palace - that was continually extended until the 19th century, the Süleymaniye Mosque complex and Sehzade Mosque complex, works of the chief architect Sinan, reflecting the climax of Ottoman architecture in the 16th century, the 17th century Blue Mosque and the slender…