It turns out that fancy, moving wall in the Elder Scrolls V: Skyrim teaser is kind of a big deal in the game. Called the Wall of Alduin, Game Informer reveals that -- like all the best walls -- it tells a story. There are several events depicted on the wall, all of them revolving around Alduin, a dragon that once terrorized the gameworld of Tamriel and has now returned to finish the job in Skyrim. Remember when you opened those Oblivion gates in Elder Scrolls IV? Yeah, well, you let Alduin back in. Good going.
Head over to Game Informer to check out an interactive version of the Wall of Alduin, which highlights and explains its different sections.