Revelation 17, verse 1 states John was shown the judgement of the "great whore who sits upon many waters." In this verse "waters," as is confirmed in verse 2, is symbolic of all the people on the earth at the end time. But who is the whore? Verse 5 tells us her name is Babylon the Great. She is symbolic of a great false religion system that will (and indeed, already has) deceive the whole world into worshipping the Beast. She is called the 'mother of harlots' or prostitutes because out of her have come 'daughters' or other religious systems that, although separate from "mom," have the same foundation of false Biblical teachings.
The prophetic ten kings of Revelation are mentioned in verse 12 of Revelation 17. They "have not yet received a kingdom" but shall reign as a king with the end time Beast power (but only for a short time). In Biblical prophecy these kings are also represented as the ten toes of Nebuchadnezzar's giant statue that are composed of iron and clay (Daniel 2) and the ten horns on the Beast, mentioned in Revelation 13, who will rule the world for 42 months.
Based on other prophecies it seems likely the ten kings will represent, for only a brief period, countries or areas of Europe. It is only AFTER their rise to power and their offering of all the resources they control (verse 13) that the Beast will concentrate its energy on FIGHTING the returning of Jesus Christ as King of Kings and Lord of Lords!