Istanbul is one of the world’s great cities. Historically known as Byzantium and then Constantinople, Istanbul straddles two continents and embraces multiple worlds—both geographically and culturally. The city is vibrant and cosmopolitan, and teeming with humanity. Minarets stud the sky, crowning Istanbul’s hilltops. Boats glide gently down the Bosphorus, while pigeons flock overhead. Exotic spice markets burst with color. Neighborhoods hold traces of the different empires that once laid claim to the Golden Horn.  It’s the kind of place where the push and pull of modernity and tradition collide. The…