While Serbia's enjoying those long May holidays, you can still do a bit more exploring around Bosnia.

If you ever decide to get married, consider Bijambare Cave for your ceremony. According to local legend, if you tie the knot inside this particular cave, your marriage will be long and happy. I haven't seen any big pilgrimages of newlyweds there, but apparently there's this one Bosnian-German couple who got married there thirty or forty years ago, and they're still living together in Sarajevo to this day. Hopefully it works out!