Part 2/15:
Depending on perspective, the big four can be subdivided or reconfigured—European civilization may be split into Greco-Roman ancient and modern Western/Russian influences, or Latin America might be integrated into a broader Mediterranean or Muslim world axis. Yet, regardless of these distinctions, these civilizations constitute the primary narrative thread of human societal development.
Interestingly, intersecting these grand civilizations is an actor that is not a civilization itself but interacts with all of them—the Eurasian steppe. This vast, often overlooked region acts as a semi-autonomous counterforce or anti-civilization, consistently producing barbarian hordes that fundamentally influence and sometimes destabilize the major civilizations.