"City" is figurative language for Satan's worldwide religious system of IDOLATRY and REBELLION against God. Setting up false saviors (false Christs) in every religion.
This "City" is the one system before which all kings, dictators, and nations have been forced to bow down throughout history, that is, the "Babylonian/Satanic" religion of idolatry.
Satan wants us to get our eyes on flesh and blood and think our battle is with a particular religious organization on earth, but though the RCC is a major religious organization that has persecuted and slain the saints of God, the "CITY" encompasses all of Satan's idolatrous religious systems.
Figurative language is very important because it is God's shorthand way of revealing spiritual realities.
For instance, the Book of Revelation uses the word "waters" and "sea" as figurative language and if you search you will find out what this refers to.
17:15 And he saith unto me, THE WATER WHICH THOU SAWEST, where the whore sitteth, ARE peoples, and multitudes, and nations, and tongues.
Then the angel explains to John the meaning of the water on which the woman (whore) is sitting: It is the peoples of the earth. Peoples, multitudes, nations, and languages designate all humanity in the book of Revelation. As in the saying, "sea of humanity"
Just keep in mind that the Holy Spirit is trying to reveal spiritual realities through the writers of the Scriptures...things not seen, rather than things that are seen. But Satan is convincing many that these things pertain to what is seen, thus Christians think the battle is between this false organization or that one, or this wicked nation or that one.
Thus, people create beliefs from one scripture that is no where else to be found in the Bible.
A good example of this is the "millenium". It is mentioned only once, in Rev 20:1-6
Figurative speech - God's shorthand to reveal something.
Revelation means an "uncovering" or "unveiling". The Book of Revelation is meant to reveal spiritual realities not conceal them.
Revelation employs apocalyptic language with highly symbolic and figurative language.
People today are unfamiliar with apocalyptic language which was popular from 200 BC to 200 AD and the early church understood it and used it during times of persecution to describe good and evil. Remember, John was exiled to the Isle of Patmos during a time of great persecution. Today, most people are prone to take things literally not recognizing the figurative use of language in the Bible.
These things that John was talking about were to "shortly come to pass".
Rev 1:1 The Revelation of Jesus Christ, which God gave unto him, to shew unto his servants things WHICH MUST SHORTLY COME TO PASS; and he sent and signified it by his angel unto his servant John:
Towards the end, John says, "Do not seal the words of the prophecy of this book, FOR THE TIME IS AT HAND" - Rev 22:10
In these two cases, "shortly come to pass" and "for the time is at hand", John is not speaking figuratively. This is straight talk now, and not symbolic language. Remember, he was writing the book to comfort the Christians to whom this letter would be sent to during this time of great persecution.
John announces at the beginning and then again at the end just so everyone would know for sure.
"Shortly come to pass..." Rev 1:1,3
"For the time is at hand... "Re 22:6,10
The literalist here, should agree. For some reason that is not the case.
This is not figurative language for a couple of thousand years, later. That would not be very comforting to the Christians of John's time.
Some think Bablyon back then was Jerusalem and the Beast that supported the Whore was Rome and although that might be very applicable for that time (in John's mind), there are still spiritual realities that do pertain to our time and every time in between the 1st century church and now. Just as the false religious system killed Jesus and many saints and employed Rome to carry out their dirty work, that same modus operandi has taken place through the centuries. As the Whore is still today, religious idolatry (Satan's "city", "Kingdom") and the beast is the political/military world that is married to the false religious system. Hence, the religious system rides the beast. Always has and always will since they are both Satanic systems, belonging to the same kingdom. The false religious system has used political and military powers through the centuries to persecute the saints of God.
The purpose of Revelation was to reveal that God was bringing judgment on Rome and Jerusalem for having rejected God and persecuting His people culminating in the destruction of Jerusalem and even Rome ceased to be a world power, later. And yet, the book of Revelation is still applicable in every century, till the end. Because this same judgment has taken place in different ways on the Satanic kingdom. I remember when Richard Wurmbrand was imprisoned for his faith and great persecution took place in Romania. Eventually, the Lord judged that ruler and the political system and that kingdom (principality) were brought down.
Revelation is a book of warning to saints then and now and in between to remain faithful and it is a book of comfort, then, now and in between, and it is still applicable generally speaking in the battle between God and Satan and the true Church and the False Church. There are still things to come to pass. It is a panoramic view of the battle between light and darkness, Kingdom vs kingdom, righteousness and unrighteousness. There is still a few more things to be fulfilled:
The final and ultimate defeat of Satan - Rev 20:7-10
The final judgment - Rev 20:11-15
The eternal destiny of the redeemed saints of God - Rev 21:1-22:5
It is really important to look at these things with spiritual eyes and not with your physical eyes and when you see these things, it really helps you to understand where the true battle is taking place and then you will not "entangle yourself in the affairs of this life".
"Thou therefore endure hardness, as a good soldier of Jesus Christ. No man that warreth entangleth himself with the affairs of this life; that he may please him who hath chosen him to be a soldier." 2 Tim 2:3
May the Lord help us all to see.
Food for thought...