Went ashore by tender which took us directly to the beautiful waterfont lined with cafes/restaurants. Having been there many times before and for two land holidays, it is a very firm favourite with a myriad of very narrow streets (no traffic apart from the occasional motor scooter). The streets are all crazy-paved with white paint in between the large slabs of stone. All the buildings are painted white and not more than 2/3 stories in height. It is very easy to get lost as it is like a maze, but you can't stray too far without getting back to base. Lots and lots of trendy shops most of which are very small.Soe lovely merchandise.
If one has long enough ashore, from the main square at the top of the town you can take a bus to a small fishing village from where you get on a colourful fishing boat which drops you off at one of five beautiful sandy bays....well worth doing.
I have been wanting to go to Istanbul for over 40 years and finally made it. What a wonderful city and one which comes in my top three (Venice and Cape Town being the other two). We took a Red Sightseeing bus which went from directly outside the port gates which was only about 100 yards from the ship. (Of course Costa never mentioned anything about this convenience or sightseeing bus). At 20 euros each we had a lovely tour and got off at the famous Blue Mosque, which was free to enter...a real must visit.
The locals were extremely friendly, helpful and genuinely pleased to please.
After going back to the ship with my wife, as it was too hot for her, I went out again on foot and walked over the Bosphorus bridge. This was facinating as underneath the roadway almost a water level, there were some 30/35 restaurants straddling both sides of the bridge which only had the middle part for navigation. The views from the eating places was simply stunning. In fact the whole city was just stunningly beautiful. Euros were accepted everywhere I went.
The port for Roma is Civitiavecchia, which is about one hour by train away from Rome and costs about 15 euros. The Port town is rather lovely especially now as they are spending a lot of money in making a really lovely wide waterfront promenade. The town itself is rather nice with a busy market at the back of the town.