Skyward Sword has 7 major dungeons. The first 3; Skyview Temple, Earth Temple and Lanayru Mining Facility, are entered in search of Zelda, whilst the following 3; Ancient Cistern, Sandship and Fire Sanctuary, are entered in search of creating the Master Sword. There are 3 major areas; Faron, Eldin and Lanayru, and each area has 2 dungeons each.
The final dungeon, Sky Keep, is located in Skyloft, and is the final dungeon in the game; with the reward being the Triforce.
