It continues to be meaningful to depict the varieties of Christianity across the world on a map, but those regional differences are being put under pressure. Within global communions such as the Roman Catholic or Anglican churches, it is becoming progressively harder to avoid the tensions between the robustly conservative doctrines and morals of the global South and the secularized and liberalized Christianity more prevalent in the Euro-American world. But the global era is also producing new global networks. These were first enabled by mass media and are now turbocharged by the internet, which allows minority Christian groups to gather and encourage one another virtually, and for tiny communities to discover that they are in fact millions strong. As populations in the rich North age and decline, the global South is coming to them and bringing its churches with it. The much-heralded phenomenon of “reverse mission” – in which the newly Christianized South sends missionaries to revive secular Europe’s faith – may not produce many results, but the influx of migrants will.