We should be able to find the interpretation in the same chapter, if one is to read scriptures in the entirety, not just a single verse.
Revelations 17:18 - the woman you saw is a great city.
Revelations 17:9 - the seven heads are seven hills on which the woman is seated.
The woman is a city. She sits on seven hills. Immediately, two cities fit the description - Rome and Jerusalem.
The better understand Revelation 17 we must back to Revelation 12 where we find the same beast, the dragon, which represents Satan (Revelation 12:9) who seats on seven hills (Revelation 17:9). Rome was a city known for being built on seven hills. The woman, or bride, in the Bible is a symbol for a church and a harlot is a symbol for the apostatized church.
Constantine as the New Rome in 326 AD to replace Old Rome as capitol of the Roman Empire. It ultimately became only the capitol of the Byzantine or Eastern Roman Empire when the western part split and finally fell c. 476 AD.
Two further comments: The Grecian Empire never truly existed since it was divided into four parts after Alexander's death. It doesn't compare with the other five empires listed. Perhaps this is why Daniel needed to see the goat and ram vision of Dan 8:3-12.
The Anglo-American "empire" has never been hostile to the Jews in the same way as the prior six entities mentioned above. In fact, it has been the opposite, so I believe the seventh kingdom is not Anglo-America.