So far we've seen a countless amount of impression pieces as Skyward Sword became more and more accessible on various conventions and events. But as the saying goes, beauty's in the details, and various people drop various details, of varying significance. This particular detail will set everyone's theorizing wheels into overdrive as it is potentially gigantic. A French preview has dropped the name of the third dungeon in the game, the one right before Link catches up with Zelda and ans obtains the lyre, as seen in the last trailer.
As a matter of fact, that very scene shown in the trailer might be happening in that dungeon, giving the huge cogwheel behind Zelda a very different meaning. So what is this dungeon?