When GOD divided the nations at Babel, this began the second world.
We previously established that, at Babel, when GOD scattered the nations, He assigned angels over them.
From that point, 2000+ years before Jesus, through the first century, angels ruled all nations except Israel, whom GOD kept for Himself.
7 “Remember the days of old,Deuteronomy 32:7-9 OSB
Consider the years of many generations.
Ask your father, and he will tell you;
Your elders, and they will tell you:
8 When the Most High divided the nations,
When He scattered the sons of Adam,
He set the boundaries of the nations
By the number of God’s angels.
9 For the Lord’s portion became the people of Jacob;
The allotment of His inheritance is Israel.
The New Testament writers of the first century referred to their present world and contrasted it to the pre-flood (aka antediluvian) world. For example, the apostle Peter wrote:
4 For if God did not spare angels when they sinned, but cast them into hell and committed them to pits of darkness, held for judgment; 5 and did not spare the ancient world, but protected Noah, a preacher of righteousness, with seven others, when He brought a flood upon the world of the ungodly …2 Peter 2:4-5 NASB
This second world was not a new planet or even a new creation of GOD, but rather, a new system of order—a new heavenly government—for the nations which would arise, grow, change, and decline from the start, at Babel, through the millennia thereafter.