"And here is the mind which hath wisdom. The seven heads are seven mountains, on which the woman sitteth. And there are seven kings: five are fallen, and one is, and the other is not yet come; and when he cometh, he must continue a short space. And the beast that was, and is not, even he is the eighth, and is of the seven, and goeth into perdition."
The above is from Revelation 17:9-11. The most popular--and wrong also--interpretation of these verses is that they refer to the city of Rome (with its seven hills, where the Vatican is). The proper interpretation is that these mountains represent the seven great empires that arose (consecutively) after Noah's flood: 1) the 1st Babylonian Empire (founded by Nimrod or Sargon the Great), 2) the Assyrian Empire (founded by Asshur), 3) the 2nd Babylonian Empire (founded by Nebuchadnezzar), 4) the Persian Empire (founded by Cyrus the Great), 5) the Greek Empire (founded by Alexander the Great), 6) the Roman Empire (founded by Julius Caesar), and 7) the Holy Roman Empire (founded by Charlemagne).
John says that five have already fallen (from his perspective on the timeline). They are: the 1st Babylonian Empire, the Assyrian Empire, the 2nd Babylonian Empire, the Persian Empire and the Greek Empire. And according to John one is currently holding power (over the Glorious Land): the Roman Empire. Then there is one that hasn't appeared yet: the Holy Roman Empire. The way I see it, John saying that this empire continuing for a "short space" pertains to this political entity having disappeared by the time the eighth empire (the Antichrist's revived Atlantis) arises (quite imminent). I've seen other explanations for the seven mountains--involving different line-ups of empires. The line-up I've given above seems the most reasonable and the most grand--in terms of far-flung history. After all my line-up begins with the first world ruler (not literally the entire world, I'm sure), Nimrod.
What about "the beast that was, and is not"? Let's look at Rev. 13:3-4: "And I saw one of his heads as it were wounded to death; and his deadly wound was healed: and all the world wondered after the beast. And they worshipped the dragon which gave power unto the beast: and they worshipped the beast, saying, Who is like unto the beast? who is able to make war with him?" The head with the deadly wound appears to have been the Roman Empire. (There may very well be a double-fulfillment for the near-fatal head wound.) Rome was a growing power in the 4th century BC. However the Celts crossed the Alps, moving down the Italian peninsula. These Celts took the city of Rome and had the Romans at their mercy. The former made it known that all they wanted was gold, which the latter readily handed over. The Celts then left and Rome was spared. So Rome was wounded in the head, as it were, which healed up. Rome went on to become a great empire, thus the question: "Who is like unto the beast?"
Revelation 17:8 says, "...and they that dwell on the earth shall wonder, whose names were not written in the book of life from the foundation of the world, when they behold the beast that was, and is not, and yet is." To me this "beast"--that once was and came close to not existing but does yet exist--was Rome. And Rome is of the eighth (Antichrist kingdom/final Babylon) and also is of the seven empires going back to Noah's flood.
Rome and every empire that would come after it--especially the revived Atlantis that is rising--would be more beastly than the preceding empires. Daniel 7:7 speaks of this: "I saw in the night visions, and behold a fourth beast, dreadful and terrible, and strong exceedingly; and it had great iron teeth: it devoured and brake in pieces, and stamped the residue with the feet of it: and it was diverse from all the beasts that were before it; and it had ten horns." The previous verse describes a leopard with four heads, which is symbolic of the Greek Empire. For Alexander moved like a leopard through the Persian Empire, bringing it to an end. After his death his empire was divided among four of his generals.
It was the Romans under Prince Titus who smashed Jerusalem and dispersed the "evil figs" (Jeremiah 24) that I wrote about two posts previous. During that siege the Jews (both Judahites and Edomites), from what I understand, resorted to cannibalism to survive--once the food ran out. You had mothers eating their own children. Jesus Christ said (Luke 13:34-35), "O Jerusalem, Jerusalem, which killest the prophets, and stonest them that are sent unto thee; how often would I have gathered thy children together, as a hen doth gather her brood under her wings, and ye would not! Behold, your house is left unto you desolate: and verily I say unto you, Ye shall not see me, until the time come when ye shall say, Blessed is he that cometh in the name of the Lord."