Vacation help - where should we go next?

The only one above I've been to is Turkey, but it was one of my favorite trips ever. The country is extraordinarily beautiful with diverse landscapes, so much history and culture, and has some of the friendliest people I've ever run into. I enjoyed my time there so much, and want to get back some day. I highly recommend traveling here.

How about Germany's Harz mountains incl. UNESCO world heritage old towns and the German Baltic Sea coast incl. Lübeck?

With 10 days I would start by looking at where I can fly to and from the quickest. Can you get non-stop flights to any of those places? If so that would be my first choice. Otherwise, my thoughts are that Croatia ( and maybe Cyprus) might be more touristy. And that maybe 10 days is not enough to do Turkey justice? Personally I think Slovenia fits most of the bill, you could dip into Croatia for some beaching.

@MarkK, thanks for the Northern Germany ideas, especially Lübeck looks wonderful.

I strongly recommend Slovenia. I was there for 2 weeks in September 2018 and I was overwhelmed by the beauty. It was very inexpensive — I think it hasn’t converted to Euro yet. Once it does, prices will likely go up a good bit. I didn’t visit Istria/the coast, as it was largely a hiking trip. I stayed at Lake Bohijn (only 30 minutes from Bled and much less crowded but IMHO more beautiful), Logari Valley, and 2 days at Plitvice Lakes in Croatia, plus a few other spots. If you can stretch your time on ground to at least 12 days, I’d recommend doing so.

For historical sights, you can't beat Turkey-Istanbul, Ephesus, Troy. Slovenia and Montenegro would probably be better for hiking.

With only 10 days, your choices will be limited.

I would suggest Croatia and Slovenia. And add Montenegro if you have time.

If at all possible, try to catch two full weeks and three weekends. You would have so much more to see with just a little more time on the ground.

Thank you everyone for the great advice!!