Board Thread:Off Topic/@comment-24099618-20140114190300/@comment-24261859-20140602001105

In a nutshell, the mortal plane is kept separate from Oblivion by mystical towers (not always literally towers; the giant robot Numidum and the Throat of the World are among the list). The Thalmor want to deactivate the towers, thus causing Mundus to phase into oblivion, destroying the mortal plane and, theoretically, allowing the Altmer to re-ascend to divinity.