I have done a good bit of travel in Europe. I have visited many major European cities, but I prefer to spend my vacation time in cities up to about a million inhabitants or so, and especially in the countryside, visiting smaller towns. My favorite city in the world is Prague, (population 1.2 million) where I lived and worked for a year in the early 2000s.
I enjoy wine and food, and much of my European travel revolves around wine and eating. Some places in Europe where I have spent time: Beaune, in Burgundy, Lyon, Provence, the Piedmont, (including Barolo), the Veneto (specifically the countryside around Verona), Croatia, including Rijeka and Dubrovnik, the High Tatras (Vysoké Tatry) in Slovakia, and Tuscany (mostly around Siena). I have also spend a bit of time in northern Spain, in Gijón in the province of Asturias, in Santander in the province of Cantabria, and in Ezcaray and Haro in La Rioja (Spain). I also have done a bit of travel in central Europe.