What is the third heaven that Paul mentions in 2 Corinthians 12:2?

In Gen 1.1 'heavens' is a dual form of the word. God created two heavens and one earth. These are heavens 1 and 2 as listed above. They are created heavens.

The third heaven is referred to as the heaven of heavens:

   2Ch 6:18 But will God in very deed dwell with men on the earth? behold, heaven and the heaven of heavens cannot contain thee; how much less this house which I have built!

Even the heaven of heavens cannot contain God. There is no container larger than God. Even this third heaven is within God himself. Since those going there have an 'out of body' type experience, it is suggested that it exists in a spiritual realm.

The Jewish sages tell us that when God created, he created the void within himself, since there was no place outside of himself. Then he created what we see, within and from the void.

With this model, the third heaven is outside of the void and within God himself. While we exist in the void, there is a separation from the essential nature of God. In the third heaven, His essential nature is experienced without separation.