We visited Istanbul in another port visit. Istanbul did not originally appeal to me so I had not booked any shore tours but when we arrived we decided at the last minute to join a tour. We went around the city in a tour bus and also visited a massive mosque. I am glad we did it because I learned a little about Turkey that I did not know. Our bank manager is certainly glad we did it because we bought a pure wool Turkish carpet for over Us$2000, that was an expensive tour.
It was also interesting because it was called "Easy Istanbul - Spanning Two Continents" because half of the city is in Europe and half in Asia. So on this trip we have covered three continents Europe, Asia and Africa!!