Originally Posted by
pinniped
There are literally hundreds of destinations in Europe where a stopover could be a lot of fun, but if you really only intend to spend 2 days at the XXX city, I'd narrow the choices to places with easy travel to/from IST and easy ground transit to/from the XXX airport.
The good thing for the OP is that there practically isn't anywhere TK doesn't fly anymore. Beats me how they can support non-stop flights like IST-LUX or IST-CTA, but they seem to be doing it.
Agree that multiple tickets of some sort will be the way to go. I've had itineraries recently where each day was a separate one-way ticket.