Revelation 17:9

Here is the mind that has wisdom. the seven heads are seven hills on which the woman is seated;

Revelation 13:18

Here is wisdom. Let him who has understanding count the number of the beast; for it is the number of a man; and his number is 666.

Revelation 17:3

And he bore me away in the Spirit into the desert, and I saw a woman who sat upon a scarlet beast covered with blasphemous names. It had seven heads and ten horns.

Matthew 13:11

"Why do you speak to them in parables?" Jesus answered. "To you it has been granted to understand the mysteries of the kingdom of heaven; but to them it has not been granted.

Matthew 24:15

"So when you see the Abomination of Desolation spoken of by the prophet Daniel, standing in the holy place let the reader take note of this,

Revelation 13:1

Then I saw rising up out of the sea a beast who had ten horns and seven heads. On his horns he had ten diadems, and on his heads blasphemous titles.

Revelation 17:7

And the angel said to me. "Why did you wonder? I will explain to you the mystery of the woman, and of the beast with the seven heads and ten horns, that carried her.

Revelation 17:18

The woman whom you saw is the great city which holds sway over the kings of the earth."

Treasury of Scripture Knowledge

Summary

And here is the mind which hath wisdom. The seven heads are seven mountains, on which the woman sitteth.

Bible References

Here

Revelation 13:18
Here is wisdom. Let him who has understanding count the number of the beast; for it is the number of a man; and his number is 666.
Matthew 13:11
"Why do you speak to them in parables?" Jesus answered. "To you it has been granted to understand the mysteries of the kingdom of heaven; but to them it has not been granted.
Matthew 24:15
"So when you see the Abomination of Desolation spoken of by the prophet Daniel, standing in the holy place let the reader take note of this,

The seven

Revelation 17:3
And he bore me away in the Spirit into the desert, and I saw a woman who sat upon a scarlet beast covered with blasphemous names. It had seven heads and ten horns.
Revelation 13:1
Then I saw rising up out of the sea a beast who had ten horns and seven heads. On his horns he had ten diadems, and on his heads blasphemous titles.