It is the interior, however, that reveals the most differences. In the East, in the Greek- and Russian-speaking world, churches are always an explosion of light and colors, which combine to reflect the divine radiance as if it were given to men as a gift from the world to come. The first thing that strikes is the passage quoted above: the cupola is the highest element of the church, thus, with its round shape, it symbolizes the cosmos. The Christ Pantocrator, ruler of all things, is the first element painted; looking down, awake, the Christ blesses all the faithful as ruler of above, of a world that is not yet but still present. The Pantocrator dominates the church, He is above everything else: thus, He is truly ruler, king. The rest of the decoration is hierarchically organized with respect to this element: the angels, the apostles, the saints, the prophets, etc., and the walls are surrounded with icons. Thus, the church in the East is a microcosm filled with divine energy, an image of the world to come and a reminder that the Christ, source of all things, is always present, transcending everything.
In the West, there are also representations of the Christ, the Mother of God, the saints and prophets. These, however, take a different form. Instead of icons, they are depicted in the form of statues and stain glass. The most strking difference comes from the representation of Christ. Here, He is typically presented not above, but facing the faithful, usually behind and slightly above the altar, overlooking everything, but lower that the highest vaults. Also, he is put on the cross, eyes closed, and not alive. Thus, the faithfull may remeber His sacrifice for us and the meaning of divine Love and Mercy. We have here a pattern that will distinguish Western from Eastern iconography: while in the East the Christ Pantocrator would necessarily get higher as the architectural plan of the church gets higher, in the West, it is not the case. The crucified Christ remains always at the same height, while the roof of the church becomes higher with the vaults.