Why You Can See Morrowind From Skyrim

What many people already suspected has been recently confirmed to Kotaku by Todd Howard, who confirmed that the reason for the presence of Tamriel's other regions in The Elder Scrolls V: Skyrim's data has not much to do with plans for add-ons or anything of the like:
Speaking with Kotaku at DICE last week, Howard says "The reason they are there - and I will not say if we are or are not using them in the future - is when we first built the landmass for Skyrim we knew we were going to have these tall mountains.

And what can you see see? We have views early in the project where you can see into the [neighbouring] province from the other game. We needed to have something [there].

It's not high detail. If you walk there, from a distance it's...yeah, the stuff is there. And the thinking is, maybe we'll use it one day, but our larger worry was, I'm going to climb up on top of a mountain and look that way. What will I be able to see there? We try to cover all those angles as much as we can."