Just one country that you're really interested in exploring all the sights in.
That would be nice !
While Hippy is enjoying himself exploring the highlands of Scotland I'll pop across to Wales. My father was born just outside Cardiff in 1884 and I'd love to roam the country.
Actually, there are quite a few countries I would like to explore.
If having to choose where to begin, I'd opt for Japan,
(and next for New Zealand).
I would love to visit the Swiss Alps. Zenimax - the creator of The Elder Scrolls Online - started a "Trip of A Lifetime" contest to send several lucky winners to countries they used to design the game. Skyrim was designed after the Swiss Alps and I'd love to visit there to see why they choose this place and to see what everything the Swiss Alps has to offer. Plus, it would be cold!
(Skyrim left; Swiss Alps right)
Maybe that this official link might be of interest to you: