The clear case in Revelation is that Babylon is Rome. This stems directly from the Daniel 2 vision of the statue, where if the head is called Babylon, so is the foot.
Conjectures for the identity of Revelation 17 vary widely, and my personal take is a little different, taking into account the end of the chapter where it says the beast will hate the harlot.
I understand the Harlot to be the principality personified by the goddess “Rome”, or “Roma”. This is Jezebel, through and through, same personality, different name.
She, “Roma” is depicted as sitting on seven hills beside the waters. She is said to “personify the city of Rome and civilization itself”. This is the same “queen of heaven” from Babylon. And, she is the same one that married Ahab in Israel and slaughtered the prophets.
She is called “the great city”, but this cannot be Jerusalem, because Israel might have been a harlot, but she was not the mother of all harlots. She is the principality because she personifies the city. Hence, she “is” the city. John is astonished because he sees the spiritual reality.
This is why the beast, the emperor, and the ten kings hate her. She was often honored in along side the emperor in the temples for that. Raising a “female” deity above them is certainly liable to cause hatred.
Proof comes in the coins of the era minted, and that the recipients of the letter of Revelation would not have understood it any other way than the city of Rome, and more specifically, the Jezebel principality ruling it. It is demonstrated through history, and should not be understood as another city, for it was this one that ruled over the kings of the Earth, something Israel did not do, and Babylon cannot fulfill in the future.