"The Revelation is obviously not a prose composition. It is a drama, a moving picture of the unfolding kingdom of Christ in a world of carnality, sin, and death — a picture taken not with a cinematograph, but with the camera of divine revelation. Again and again throughout the book of Revelation we have noted that the vast majority of the events portrayed in the visions of John takes place in one of three realms — heaven, earth, or sea. These, of course, are not the literal, outer heavens of the universe, nor the physical planet earth, nor the actual seas of water. As we know, these symbolize three realms of life through when we pass on our journey from the depths of the kingdom of darkness unto the heights of the kingdom of life and light in Christ. As the voice from heaven declared, "Rejoice, ye heavens, and ye that dwell in them. Woe to the inhabiters of the earth and of the sea! for the devil is come down unto you…" (Rev. 12:12)."

Much more in the text:

https://www.godfire.net/eby/rev180.html