The Arcane Congress is one of the largest centres of arcane study in Khorvaire, based out of the floating towers that hover above the village of Arcanix. The towers have always been the headquarters of the Arcane Congress, and over the centuries they have turned it into a monument to the power and beauty that is possible with magic.
On top of this, the Arcane Congress is also a branch of the Aundairian government. During the war, the floating towers were both mobile research facilities and also terrifying siege weapons, as one might expect from a floating tower full of some of the most powerful wizards in the world.