NOTE:  John is presented a vision in 1-6, then is told what the vision represents in 7-18.  Commentaries have such different ideas.  Going to put down what stands out to me.

Revelation 17:1  “…the judgment of the great harlot…”
Bible refers to worship of anyone or anything other than God as harlotry.  I think the great harlot is the religious system that has been set up for people to worship the dragon and the beast.  All of it is satan trying to be God.  He sets himself up on earth through the person of the Antichrist and wants all to worship him.

2  “…the kings of the earth committed fornication, and the inhabitants of the earth were made drunk with the wine of her fornication”
Rulers went along with the system, even if they didn’t fully agree or participate for the sake of business and commerce.  Some were fully engrossed in it.  Those are ones who took the mark.

3  “…having seven heads and ten horns”
The beast John saw earlier.  The kingdom of the Antichrist.  From what the angel will say, it is the kingdom through the years, like the statue of Daniel.

5  “…BABYLON THE GREAT…”
Idea of Babylon goes all the way back to the Tower of Babel.  Men tried to set themselves up as equal with God, the ones in charge of everything.  All systems of false religion since then are just copies.  Possibility that the physical capitol of the Antichrist is located in Babylon as close to the point of the Tower as they can find.  Think the present day Babylon is close to where they think the tower was.  Pretty much where Nebuchadnezzar had it.

6  “…drunk with the blood of the saints and with the blood of the martyrs of Jesus…”
False religions have always been completely intolerant of God and Christianity.  They cannot abide any truth in worship and must destroy any opposition.

8  “…beast that you saw was, and is not, and will ascend out of the bottomless pit and go to perdition…”
Description of satan, the dragon.  He has been around since the beginning, will be cast into the bottomless pit for the Millennium, then will be released for a short time before being cast into the lake of fire.

9-11  “…seven heads are seven mountains…seven kings…Five have fallen, one is, and the other has not yet come. And when he comes, he must continue a short time…the beast…is himself also the eighth, and is of the seven, and is going to perdition”
Appears to speak of the kingdoms of the Antichrist throughout history as Daniel saw them.  Mention of the seven mountains or hills causes many to think the final king must be part of the old Roman empire as Rome was said to sit on seven hills.  May be part of it, but I think it may just represent the ruling kingdoms of each time period.  Five of the kingdoms were gone by the time of John, and Rome was in power then.  One yet to come would be the Antichrist at the end time.  Satan, the beast, would possess the Antichrist at some point which would make him the eighth.  Saying he is of the seven and is going to perdition identifies him as satan who has been a part of all rebellion throughout history.

12-14  “…ten kings who have received no kingdom as yet, but they receive authority for one hour as kings with the beast…will give their power and authority to the beast…will make war with the Lamb…the Lamb will overcome them…”
Rulers who will be around during the reign of the Antichrist.  The more I look at this, the more it looks like the Antichrist doesn’t conquer the world, but instead sets himself up with the cooperation of the other world rulers.  He does so by supplanting three.  Not sure if it is three of the ten or three others.  Eventually the ten will rebel and be brought to the Middle East to battle.  They obviously will fight against Christ, but they may have also come to destroy the Antichrist’s kingdom.  They are no match for Jesus.  He destroys them with mere words.

16  “…the ten horns which you saw on the beast, these will hate the harlot, make her desolate and naked, eat her flesh and burn her with fire”
Sounds like the other rulers finally had enough of the system set up by the Antichrist and destroy it.  It is all God’s plan of judgment for the Antichrist.  He doesn’t have to do it Himself, He is Lord of all and can use even the heathen for His purposes.

18  “…woman whom you saw is that great city which reigns over the kings of the earth”
The seat of power of the Antichrist, the city of Babylon.  Directing the world in all religious and business matters.  When they’re brought to Megiddo to fight, I’m not sure if they were brought to destroy the Antichrist’s kingdom and then turn on Jesus, or if they are brought to destroy and then are there conveniently for Jesus to destroy.  Will be interesting to see how that plays out.

I hope you enjoy reading and studying His word.  May it accomplish what He desires.  Please feel free to comment or post questions.  Thanks for reading!

Scripture taken from the New King James Version®. Copyright © 1982 by Thomas Nelson. Used by permission. All rights reserved.