What are the headquarters in marvel Ultimate Alliance

You start off in Stark Tower, then you move to the Sanctum Sanctorum after defeating Mandarin.
You move to Valhalla after the level in Mephisto's Realm, and you're in Attilan for a while after you're 'killed' by Dr. Doom.

There is also a dark verison of Stark Tower you go to at the end of the game, but that's not really a headquarters.