Great Bay Temple

The Great Bay Temple is the third dungeon in.

Entrance to the Temple
The Temple can be seen far away from the Great Bay Coast and Zora Cape. The Temple is victim to a curse that leaves the sea of Great Bay murky. Once Link recovers the Zora Eggs laid by Lulu and takes them to the Marine Research Laboratory, Link learns the "New Wave Bossa Nova", a melody he must play while in Zora form to summon a Giant Turtle just outside the back entrance of Zora Hall so that the Turtle can take him to the Temple.

Themes and Navigation
To progress within it, Link needs to open numerous water valves that are part of an extremely complex network of pipes. Doing so enables the functionality of water-based elevators that help Link reach new places. Eventually, he has to invert the direction of the water's continuous flow so that the flux can take him to new parts of the Temple.

As an indication that Termina is more technologically advanced than Hyrule, the Great Bay Temple is actually one big factory, with churning gears, rooms and passages illuminated by neon lights (which suggest that part of the energy provided by the water motion is turned into electric energy to ensure the operability of all the machinery), and the previously cited water-based elevators and valves. Link has to activate the yellow-colored elevator to gain access to most of the Temple itself, the red-colored elevator to gain access to the rotating lever that helps Link to invert the water's flow direction, and the green-colored elevator to gain access to the entrance to the boss's lair.

The key items in this dungeon are the Ice Arrows, which Link can acquire after defeating the mini-boss Wart. He later uses Ice Arrows to defeat the Mad Jelly and Gekko for the Boss Key. The Ice Arrows are also essential to navigate certain areas by means of freezing the surface of deep water and even some enemies for use as platforms, which can be used to reach valves that would be otherwise inaccessible.

If Link is able to collect all 15 Stray Fairies in the dungeon and return them to the Fairy's Fountain, his reward will be a Defense upgrade. The boss of this Temple is the Gargantuan Masked Fish: Gyorg. After its defeat, Link receives a full Heart Container and Gyorg's Remains.

Trivia

 * The Temple's exterior when viewed from Zora Cape is in the shape of a giant fish.