With the theory of Rev 17 is Rome, ie is Babylon and built on seven hills you have the problem that Rome isn't the Catholic Church. Vatican City-State only existing since1929 is west of the Tiber and is on only one hill, which is not even one of the hills among the seven hills of ancient Rome, those seven hills of Rome are east of the Tiber. t Per internet, Lisbon, Istanbul, and several cities in the United States such as Lynchburg and Cincinnati claim to be built on seven hills. How about Jerusalem's seven hills? Those hills are Mount Scopus, Mount Olivet and the Mount of Corruption (all three are peaks in a mountain ridge that lies east of the Old City), Mount Ophel, the original Mount Zion, the New Mount Zion and the hill on which the Antonia Fortress was built. That's per Wikipedia which has lists of cities all over the world that are built on seven hills, about 100 of them, which have political systems and political power. Present day Rome is political and still involved in world politics. https://en.wikipedia.org/wiki/List_of_cities_claimed_to_be_built_on_seven_hills edit to add: re Babylon 'the great city' discussed in Revelation, Rev 11 states that the great city is where the Lord was crucified. That points to Jerusalem as your seven-hilled suspect.