Sanctuary Fortress

An ancient place of Luminoth study, the Sanctuary Fortress is the vast stronghold that makes up Sanctuary Sector. It is built high on the cliffs of Temple Mountain, overlooking what appears to be an enormous city. When the Ing attacked, the Luminoth used the Fortress as a defense against the Ing. Only mechanoids such as the Quad MB, Quad CM, Rezbit, Octopede, and the Ingsmasher remain in the Fortress. Now serving the Ing, the mechanoids see Samus Aran as a foe they must terminate immediately. The Fortress' Dark Aether counterpart is the Ing Hive.

Areas and Main Rooms
The Sanctuary Fortress is clearly divided into two main areas:

Lower Level
Its rooms form a "T" shape. Its tips contain the elevators to all the other Aether areas (excluding the Great Temple)

Main Rooms

 * Sanctuary Entrance
 * Reactor Core
 * Hall of Combat Mastery
 * Main Reserch

Upper Level
The Upper Level is only accessible through two elevators from the Lower Level.

Main Rooms

 * Sanctuary Temple
 * Main Gyro Chamber
 * Aerie
 * Watch Station

Glitch
One room in the Sanctuary Fortress has perhaps the most fatal glitch in Metroid Prime 2: Echoes. In Main Research, there are three sonic locks to deactivate. If for whatever reason Samus leaves and re-enters the room without deactivating all three locks, Samus will not be able to open the door, thus Samus cannot continue, except for restarting the entire game or perform what is known as a Kip Dash. 1 However, if Samus hasn't saved the game after discovering this glitch, she can simply restart the game from the last save point.

Trivia

 * Pieces of another Quadraxis can be seen in the Sanctuary Temple.
 * The advanced technology that this area presents is found nowhere else on the rest of Aether. It is therefore odd to some when they first see that the Luminoth constructed this technological marvel.
 * Interesting enough, when you ride the elevator from the Temple Grounds to Sanctuary Fortress, you travel downwards, yet when you look over the elevator side of the Fortress from Sanctuary Entrance, there is no structure leading upwards, suggesting that the developers overlooked this small flaw, or the elevator somehow warped, seeing the Fortress is in the sky, not underground. The elevator controls also call the areas "Sanctuary Cliffs" and "Luminoth Temple", further hinting that this area was overlooked.
 * According to artwork, its original name may have been the "Digital World".
 * This area may be one of the first places on Aether that the Luminoth colinized, because it is stated that when the luminoth first came to Aether, they lived on the cliff sides, and the elevator controls call the areas "Sanctuary Cliffs".