Royal Family's Tomb
The Royal Family's Tomb is located at the back of the graveyard in Kakariko Village. The only true reason to ever visit this area is to retrieve the Sun's Song.
When Link arrives outside of this large tomb, he can play Zelda's Lullaby. The grave will break open, causing a hole to open in the ground, indicating there's something down below. Down there he will find some Keese. Kill them to open the nearby door. In the next room there is a small congregation of three ReDeads, but they can easily be avoided. Once Link gets to the next room there is a headstone, which he can read to learn the Sun's Song. This song allows Link to change night into day and vice versa. This is very helpful, especially in Hyrule Field when the Stalchildren come out at night.