I still can't decide this theme is too cool. Leaning towards beach but mannn having a palace or a theme park all to you and your friends sounds so fun too.
I've ALWAYS dreamed of wandering in museums, palaces, castles, or even schools and the like by myself, without all the visitors, is that just me? To me they're so cool as just, places to be in. Theme parks are way too artificial to me but they have so much fun factor with friends man...
I like to think that you can still go to a beach by yourself, but realistically... that's rare, and that's not even counting all the goddamn pollution. Beaches are just the realest place between the three, spending an entire day at the beach with friends is so nice, so I might go with that. I do love swimming too, so that helps
Maybe that's boring of me, but you really can't go wrong with nature