The fall of Jerusalem in 586 BCE represents the nexus (or crossroad) of all of history, Western Civilization in particular. Before the fall, the Jews and descendants of Abraham were partakers of a National Covenant with God Almighty. In Jeremiah chapter 11 they were warned that calamity would overtake them if they did not repent. But they did not repent and Jerusalem finally fell in 586 BC in Jeremiah chapter 52 .
What if they had repented and turned back to God? History might have looked very different. God was able to deliver the children of Israel from the Pharaoh of Egypt in the time of the Exodus. He performed mighty acts that today we call miracles. The ten plagues, parting of the red sea, manna from heaven, water from the rock, defeat of Jericho , etc.
It is not hard to project the outcome of history for a people who were in a covenant relationship with God Almighty. Nebuchadnezzar would not have taken Jerusalem. In fact, it is entirely plausible to think that, with God’s help he would have been routed and finally defeated, thus expanding the territory of Israel to the Mesopotamian region. Then the other great power would have been defeated, Egypt. Finally, we would not see the rest of history that has unfolded–no Persians would have defeated Babylon, no Alexander the Great would have defeated the Persians, no Roman Empire would have defeated the Greeks, and so on.
Western Civilization today would be Jewish in culture, and temple worship to God Almighty would continue until the coming of the messiah.