In the Centre

Centermages are the guys, that draw power for their magical activity from a special configuration of objects in space.
A source of such power can be found in any object located in the center of another object or its projection, any concentric shapes, or the mage himself, when located in the center of some confined space.
Therefore, it is not surprising, that their concentric towers are always built in the center of cities, or natural geological formations. (a volcano crater, for example, is a perfectly normal place for it)