Mystery Babylon being Rome is an anti-Catholic concept as old as the hills, no pun intended, this very prejudice suspect of having real interpretive validity. Interesting of the KJV is the woman sits on seven mountains, not hills, and mountains are likened to kingdoms, and I recall a study a long time ago that the word is, in fact, not the best word for hills. Also, it's no big whup mystery, if the reference is the seven hills of Rome, wouldn't have been so mysterious in John's time or ours, this famous adage of Rome: pretty lousy encryption? I see the seven mountains as historic empires of man, all of which have Satan at the heart, all of them, throughout history, spiritual Babylon, since Nimrod, with Satan ruling through unGodly men, that ultimate last empire, the eighth, literally trying to enthrone Satan. Anyway, something for you to ponder, while awaiting the inglorious appearing of your cursed hopelessness, the Antichrist, to come like a thief in the night.