What do the seven heads and seven mountains in Revelation 17 represent?
The seven heads are seven mountains, meaning seven nations with seven rulers, prime ministers or kings, on which the woman, the religious system, sits. They are also seven kings: three have lost identity, one is, one is yet to come, and the beast, Antichrist, is an eighth.
Les explains that Revelation 17:9 identifies the seven heads as seven mountains—seven nations with seven prime ministers, kings, or whatever one calls them—on which the woman sits. The woman is the religious system taught earlier in the chapter. He notes there are seven kings: three have already lost their identity; ten started, three were usurped by seven; one is, and the other is not yet come, and when he comes he must continue a short space. Les suggests this may be another world leader or European leader arising in that interval. In verse 11, he prefers to see the beast as the old Roman Empire that was seemingly dead and gone but now reappears with all its attributes; the man Antichrist will head it up, and he is the eighth. Les also points out that numbers have value in Scripture: three refers to the Godhead/deity, five is grace, and six is man, created on the sixth day.
And here is the mind which hath wisdom. The seven heads are seven mountains, on which the woman sitteth.