Temple of Light

The Temple of Light, also known as the Light Temple, became the resting place of the Triforce during the Era of Chaos, when it was built by the ancient Sage Rauru at the center of the Sacred Realm. It is the only known elemental temple that is not located directly within Hyrule. It can be accessed only through the chamber of the Master Sword inside the Temple of Time. By withdrawing the Master Sword from the Pedestal of Time, a portal opens to the Sacred Realm, which leads to the Temple of Light.

Chamber of Sages
The Temple of Light, unlike all other temples in Ocarina of Time, is not an explorable area. Only one of its rooms is visited: the Chamber of Sages, which is where the Sages meet.

After Link withdraws the Master Sword from the Pedestal of Time, his spirit is sealed away in the Chamber of Sages due to him being too young to bear the title of the "Hero of Time". Since Link's action opened the gate to the Sacred Realm, Ganondorf took this opportunity to gain access to the Sacred Realm, eventually reaching the Temple of Light and taking the Triforce for himself. While the Sacred Realm transformed into the Dark World, Rauru used his powers to keep the Chamber of Sages intact.

Seven years pass, and Rauru, the Sage of Light, awakens Link in the Chamber of Sages now that he is old enough to be considered the Hero of Time. Rauru explains Link's fate and grants him the Light Medallion to add to his power, sending off the young hero to awaken the other five Sages so that they may add their might to Link and aid him on his quest to save Hyrule from Ganondorf's rule.

Though Link is not able to visit the Temple of Light on his own, he is always warped to the Chamber of Sages every time he awakens a Sage. Here, the Sage bestows their powers to Link in form of a medallion before returning to Hyrule again.

At the end of the game, after Link gives the final strike to Ganon and Princess Zelda calls upon the power of the Sages to seal Ganondorf away, Rauru and the other five Sages appear inside the Chamber of Sages to send King of Evil into the void of the Evil Realm.

Theories

 * The Pyramid of Power in A Link to the Past is believed by some to be the Temple of Light, due to its location in the Sacred Realm, its appearance in the game's prologue speaking of the Sacred Realm, as well as the large Triforce marking in the pyramid's main chamber (where Ganon is fought).
 * It is possible that the Temple of Time of Twilight Princess is actually the Temple of Light. To explore the temple, Link must enter a portal into what seems to be a parallel world. The portal is created with the Master Sword, also a key to the Sacred Realm. Thus, it is possible for this "parallel world" to be the Sacred Realm, making this part of the Temple of Time the Temple of Light. Additionally, the dungeon is light-themed and is decorated with markings of the Light Medallion.

Trivia

 * The music in the Chamber of the Sages is a looped version of the music that plays when Princess Zelda tells Link the Legend of Hyrule earlier in the game.
 * It has been shown via emulation hacks (the debug rom) that the platforms in the background are, in fact, solid, and with aid of another hack it's possible to "visit" them. It is unknown whether this is a trace from the beta version of Ocarina of Time or just a glitch.
 * Despite not being explored, the temple still receives recognition as the "Light Room" in Ganon's Castle, this along with the effect of the Light Medallion still existing in Ocarina of Time's data leads Zelda hackers to believe that the Temple of Light was a dungeon in the beta of Ocarina of Time but was later removed.