Realistically all European civilizations and their offshoots are descendants of Rome to one degree or another. This same area is also in certain circumstances k

Realistically all European civilizations and their offshoots are descendants of Rome to one degree or another. This same area is also in certain circumstances known as "Christendom" and at least part of the reason Christianity was able to spread as wide as it did is that it was the official religion of the Roman Empire by the 3rd century AD. From here the entirety of Europe, the Americas, large swathes of Africa, and many nations in the South Pacific carry on traditions descended directly from this legacy. There is obviously a lot of variation within these societies but I would argue that the core beliefs of the people within them are noticeably and identifiably "Christian" even if these people no longer believe in God or engage with the bible in any significant way.