Great Fairy Fountain
From Zelda Wiki.org
In Ocarina of Time, the Great Fairies offer Link a variety of power ups, such as the magic meter, Din's Fire, Nayru's Love, and Farore's Wind, among other useful abilities.
The great fairies play a somewhat different role in Majora's Mask, in which the great fairies have been separated into several stray fairies scattered throughout the game's temples. By collecting stray fairies from within each temple and bringing them to their respective fairy fountains, Link could restore the Great Fairies to their original forms. This would result in Link obtaining useful power ups, such as an improved spin attack, extended magic meter, upgraded defense, and the most powerful sword in the game, the Great Fairy's Sword. Unlike in Ocarina of Time, all of these power ups are entirely optional.

