It naturally depends on your goals, but choose somewhere you love to visit frequently if you’re looking for a vacation property. Coastal areas in Spain, Portugal, or Italy are great options for this since they have strong tourism potential if you want to rent it out.
If you’re focused more on investment, emerging markets or cities with rising property values are the smarter choice since central European cities can be too pricey. The countryside or certain parts of South America would likely provide higher yields. Just be mindful of local laws and how easily you can travel there from your primary residence.