I’m sure you’ve already seen the map of beer vs wine vs spirit drinkers. It’s limited to Europe, and on seeing it one may mentally overlay a map of Protestant vs Catholic vs Orthodox. I recently heard of another division of Europe, the Hajnal line. It’s strictly binary rather than a three-part division, but interesting nevertheless. It’s based on “nuptiality”, basically whether everyone marries young (more accurate explanation at the link). But as “hbd chick” points out, it also maps quite well onto the Iron Curtain. Emmanuel Todd is cited as claiming that all communist nations had a history of strong patrilineal lineages, which the western church and its marital traditions apparently disrupted.