Now it’s true that we’re not talking about all-new experiences; while two of the dungeons have never before been run, the Divine Fortress is a returning PvP battlefield that might be a little different than before.
So what are the fresh faces on the Aion block? The Holy Tower is a six-player dungeon that branches off of the Divine Fortress and can be only run by players level 66 and higher. Alternatively, the Mirash Refuge is a solo, secret instance in the Fortress that involves a necromancer attempting to summon undead horrors. The catch with this last dungeon is that only the faction that currently controls the Divine Fotress has access to the instance, so you might be out of luck until your side gets its act together.
Source: Aion