Flag of SloveniaTake the flag of Russia and add a little something extra, or rather turn the Serbian flag upside down smack a cool shield of arms on it. Walla' you get Slovenia & Slovakia.
Here are two nations that came to be after the dissolution of the Soviet Union, as outbound allies to the ill fated socialist experiment that went so horrible wrong. Czechoslovakia broke apart rather peacefully to give us wonderful Slovakia while Yugoslavia violently imploded to give us pleasant Slovenia.
Both of these nations are mostly Catholic, but all kinds of religious & other social groupings still exist. Besides Slovenia is right next to Italy...waddaya' expect!?
Although their flags are strikingly similar neither Slovenians nor Slovakians can understand each other. However Slovakians can get by with Czech, and Slovenians can get by with 'Serbo-Croati-Bosnian'.
Flag of Slovenia
Historically Hungary played a dominant role in their society until the Turks beat em' up. Since then they have gone on a wild political ride as the Western World made peace with itself. Now they are happy quaint friendly European nations that everyone should visit.
Slovenia has one colour that Slovakia does not have: three charming yellow stars above the white alps.