Great Bay Temple

The Great Bay Temple is the third dungeon in Majora's Mask. To open the temple Link must play the New Wave Bossa Nova while in Zora form to summon a turtle to take him to the temple. In this Dungeon Link is able to get the Ice Arrows after defeating the mini-boss Wart, and uses them to defeat the Mad Jelly and Gekko for the Boss Key. If Link is able to collect all 15 stray fairies in the dungeon and return them to the Great Fairy Fountain, his reward is a Defense upgrade. The Boss of this Temple is the  Gargantuan Masked Fish: Gyorg. After his defeat Link receives a full Heart Container and Gyorg's Remains.

As if to prove that Termina was more technologically advanced than Hyrule, the Great Bay Temple is actually one big factory, with churning gears, water-activated elevators, and power plants.

A Link In Time
As stated before, the Great Bay Temple is a perfect example of Termina's technological advances. No one knows for sure just how the Zoras overcame such engineering feats. Both Termina and Hyrule share advances in technology so ancient that none of the current inhabitants can tell of their origins. However, most technology within the Zelda series seems to be centered around wind, water, and earth powered machinery.