Do the Destinations cards show countries or cities?

One or the other, never a mix. Set it with Cards Show in Site Settings, on the Content Categories tile (it shows when your category is Destinations). Automatic (the default) shows one card per country, unless almost all of your episodes are in one country; then it shows one card per city or area inside it, such as Rome, Florence and Sicily. If you add episodes from new places later, Automatic picks again. The note under Cards Show says what it picked and why, for example "Right now: Countries. Your episodes visit 17 countries."

Choose Countries or Cities and areas to decide yourself; the block then stops switching until you choose Automatic again. Your pins, hidden cards and added cards are kept for each choice, so switching back restores them.

A region that spans several countries, such as the Caribbean, is not a card. An episode about it counts toward each country it names; if it names none, it is on no card, and you can add it to a country yourself.