Light Tower

The Light Tower is located at the south end of Skyloft, found within The Plaza. After Link defeats The Imprisoned for the first time, he heads to Skyloft and asks Gaepora about the lyrics of the Ballad of the Goddess. He reveals that there is a second verse to the song that mentions two sails. Link realizes that this refers to the two windmills on either side of Skyloft, and he can use his Gust Bellows to turn them both toward the Light Tower after locating the missing propeller from one windmill on the Surface.

Once both windmills face the tower, a platform will rise out of it's center. Link can then go to the platform and play Ballad of the Goddess on his harp while Fi sings. This will create a beam of light that leads into the Thunderhead, allowing Link to reach the Isle of Songs.