Bevelle

Originally a powerful machina city, rivalling even Zanarkand. After being defeated by Zanarkand and Sin, Bevelle became the center of the Yevonite church. A castle lays benieth Bevelle where the Fayth of Bahamut lays. Also, it's the place where Via Purifico can be found.

FF X: Maester Mika rules over here.

FF X-2: Now the headquarters of New Yevon, Bevelle's secrets include an underground labyrinth below the Cloister of Trials, whose heart is the hiding place of Vegnagun (or used to be). The Via Infinito can be found in a portal here.