And the great city was divided into three parts, and the cities of the nations fell: and great Babylon came in remembrance before God, to give unto her the cup of the wine of the fierceness of his wrath (Revelation 16:19).
And there followed another angel, saying, Babylon is fallen, is fallen, that great city, because she made all nations drink of the wine of the wrath of her fornication (Revelation 14:8).
Babylon is destroyed by the ten kings who hate her and will burn her with fire (Revelation 17:16). This must happen before Jesus returns because these same kings are gathered with the beast to make war with Jesus Revelation 17:12-14). Also, in Revelation 19 people are rejoicing over the fall of Babylon just before Jesus returns.
Revelation 17 and 18, Isaiah 13, and Jeremiah 50 and 51 reveal more about Babylon in the end times. The call to God’s people is to come out of Babylon (Revelation 18:4, Jeremiah 51:6).