And yet, despite everything, it’s still not Constantinople. I’m beginning to think that I can’t go back to Constantinople. Our last full day in Istanbul, and kind of the last day of the trip. Tomorrow morning we grab breakfast, then a car takes us to the airport, then the next stop is a couple of hours in Singapore before the final stretch home, where a dog should be very happy to see us. Today was all about commerce: Byzantium/Constantinople/Istanbul has been a centre for trade for a while, like most of its history. Marco Polo was here (though I don’t think he graffitied the Hagia Sofia). Out of all this…