We left off on Rev.18: 7 the other day.  What we are seeing is the past, present and future judgements that befall Christianity .  John is using allegorical statements about the carnal and spiritual fornication with the gods and goddesses that were worshiped in Babylon 5 BC.  This was during the exile of the Jewish people after the fall of the first temple.  We already know that the Holy Roman Catholic Church is identified in Rev. 17. This was the seat of power in the 1st century.

9: And the kings of the earth, who have committed fornication and lived deliciously with her, shall bewail her, and lament for her, when they shall see the smoke of her burning,
10: Standing afar off for the fear of her torment, saying, Alas, alas, that great city Babylon, that mighty city! for in one hour is thy judgment come.

Rome was a crossroads for trade throughout the known world.  Kings and emissaries would come and pay homage to the papacy and their gods.  Over the course of time the papacy gained political power and religious power over the governments of the western hemisphere.  As Christ stated in the gospels judgement will come as a thief in the night.  Her glory will be no more the wealth that she acquired.
11: And the merchants of the earth shall weep and mourn over her; for no man buyeth their merchandise any more:
12: The merchandise of gold, and silver, and precious stones, and of pearls, and fine linen, and purple, and silk, and scarlet, and all thyine wood, and all manner vessels of ivory, and all manner vessels of most precious wood, and of brass, and iron, and marble,
13: And cinnamon, and odours, and ointments, and frankincense, and wine, and oil, and fine flour, and wheat, and beasts, and sheep, and horses, and chariots, and slaves, and souls of men.
14: And the fruits that thy soul lusted after are departed from thee, and all things which were dainty and goodly are departed from thee, and thou shalt find them no more at all.
15: The merchants of these things, which were made rich by her, shall stand afar off for the fear of her torment, weeping and wailing,

Where there was once great wealth is now laid barren by the judgement of the Lord.
16: And saying, Alas, alas, that great city, that was clothed in fine linen, and purple, and scarlet, and decked with gold, and precious stones, and pearls!

This again is referencing the Holy Roman Church and her splendor and wealth.
17: For in one hour so great riches is come to nought. And every shipmaster, and all the company in ships, and sailors, and as many as trade by sea, stood afar off,
18: And cried when they saw the smoke of her burning, saying, What city is like unto this great city!
19: And they cast dust on their heads, and cried, weeping and wailing, saying, Alas, alas, that great city, wherein were made rich all that had ships in the sea by reason of her costliness! for in one hour is she made desolate.

Again the warning is given again in the twinkling of an eye the church will fall.
20: Rejoice over her, thou heaven, and ye holy apostles and prophets; for God hath avenged you on her.
21: And a mighty angel took up a stone like a great millstone, and cast it into the sea, saying, Thus with violence shall that great city Babylon be thrown down, and shall be found no more at all.

The saints and the blood of the apostles will be avenged by our Lord.
22: And the voice of harpers, and musicians, and of pipers, and trumpeters, shall be heard no more at all in thee; and no craftsman, of whatsoever craft he be, shall be found any more in thee; and the sound of a millstone shall be heard no more at all in thee;
23: : And the light of a candle shall shine no more at all in thee; and the voice of the bridegroom and of the bride shall be heard no more at all in thee: for thy merchants were the great men of the earth; for by thy sorceries were all nations deceived.

The blood of the bridegroom and the bride will be avenged.  We can see the slaughter of the Jews and Christians in the past by the Holy Roman Catholic Church.   The walls of the vatican are slowly crumbling from the current sex scandals in Italy to their anti-semitic view towards the Jewish people and the willingness to bring muslims into the fold.

If you look at Rev. 19 the covenant of marriage between a man and women will be be restored with Christ as the head of the Church somewhere in the future.

Christ never designated a church, Roman Catholic or otherwise, He is the Church.

Have a great weekend.