Where Should I Go?

I'm off to Europe, but don't know where to wander.

I’m going to north-central Europe in mid-Summer. Say I have a 7 to 9 day vacation after that. Where should I go from there?

I’m not particularly well-traveled.

I’ve previously been to Killarney and County Kerry (1987), Dublin (1965), London (1980), Oxford (1994), Cotswolds and Bath (1987), Amsterdam (1980), Rotterdam (1965), Brussels and Waterloo (1994), Rudesheim am Rhein and Munich (1980), Paris, Dijon, Nice, and Avignon (1980), Monaco (1980), Zurich, Geneva, St. Gallen, and Grindewald (1980), Salzburg and Innsbruck (1980), Milan, Florence, Sienna, Rome, and Brindisi (1980), Corfu, Athens, and Poros (or some other island not too far from Athens) (1980), Moscow (2001) and Bodrum / Halicarnassus, Ephesus, and Istanbul / Constantinople (2009).

I have not been to Scotland, central or eastern Germany, the Nordic countries, the Baltic states, Iberia, the northern western Slavic countries (e.g., Poland, Czechia, Hungary), the Balkans (Slovenia sounds interesting), or North Africa.

Tourist attractions I haven’t been to include Vienna, Venice, and Barcelona.

My opinion in 1980 from six weeks of backpacking around core NATO countries was that Italy was the most entertaining country, with perhaps Sienna or Salzburg as the peak. Perhaps I like small cities best?

What do you think I should visit?