The symbols being refered to in Revelation are a return to biblical imagery.
Since the start of the Bible certain ideas were layed out and were built up upon by Moses, and Isaiah and Jeremiah etc.
By the time we get to John and Revelation there are well thought out references to images that were established through the history of Isreal...
Deuteronomy 31:16 "The LORD said to Moses, "Behold, you are about to lie down with your fathers; and this people will arise and play the harlot with the strange gods of the land, into the midst of which they are going, and will forsake Me and break My covenant which I have made with them."
Israel will become the harlot
Isaiah 1:21 "How the faithful city has become a harlot,She who was full of justice!Righteousness once lodged in her,But now murderers."
Jerusalem has become the Harlot
Jeremiah 3:6 "Have you seen what faithless Israel did? She went up on every high hill and under every green tree, and she was a harlot there."
Ezekiel 16: 2 & 26- 2"Son of man, make known to Jerusalem her abominations" 26"You also played the harlot with the Egyptians, your lustful neighbors, and multiplied your harlotry to make Me angry."
Hosea 4:12 "My people consult their wooden idol, and their diviner's wand informs them;For a spirit of harlotry has led them astray,And they have played the harlot, departing from their God.
Hosea 5:4 Their deeds will not allow them to return to their God.For a spirit of harlotry is within them,And they do not know the LORD.
Hosea 4:15 "Though you, Israel, play the harlot"
Revelation 17:1 "Then one of the seven angels who had the seven bowls came and spoke with me, saying, "Come here, I will show you the judgment of the great harlot who sits on many waters,"
So now by the time we get to Revelation we can finally understand....
The Doom of Babylon
1 Then one of the seven angels who had the seven bowls came and spoke with me, saying, "Come here, I will show you the judgment of the great harlot who sits on many waters,
2with whom the kings of the earth committed acts of immorality, and those who dwell on the earth were made drunk with the wine of her immorality."
3And he carried me away in the Spirit into a wilderness; and I saw a woman sitting on a scarlet beast, full of blasphemous names, having seven heads and ten horns.
4The woman was clothed in purple and scarlet, and adorned with gold and precious stones and pearls, having in her hand a gold cup full of abominations and of the unclean things of her immorality,
5and on her forehead a name was written, a mystery, "BABYLON THE GREAT, THE MOTHER OF HARLOTS AND OF THE ABOMINATIONS OF THE EARTH."
6And I saw the woman drunk with the blood of the saints, and with the blood of the witnesses of Jesus. When I saw her, I wondered greatly.
It's obvious that the Whore of Babylon is Jerusalem. And these chapters are refering to Jerusalem's punishment.
These images of harlots and harlotry was passed on by Moses and through the prophets until it was realized and explained by John in Revelation. So the symbol isn't a symbolic or literal but a well formed and understood biblical image.
The bible will interpret itself... ALL of itself.