Once called Constantinople, the former capital of the Byzantine Empire is the only city in the world to straddle two continents: Europe and Asia. This is the Golden Horn, the door between East and West, and your first vision of its domes and minarets is unforgetable. Hagia Sophia, the Blue Mosque and Sultan treasures in Topkapi Palace await - as does the Grand Bazaar, laden with carpets, beaten brass and spices from afar.