Istanbul - Capital of Three Empires, Turkey (164/418)

Strategically located 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 two thousand years. Its masterpieces include the ancient Hippodrome of Constantine, the 6th-century Hagia Sophia and the 16th- century Suleymaniye Mosque, which are now jeopardized by overpopulation, industrial pollution and uncontrolled urbanization.