In Spe Salvi the Pope makes the following point:
In the arrangement of Christian sacred buildings, which were intended to make visible the historic and cosmic breadth of faith in Christ, it became customary to depict the Lord returning as a king—the symbol of hope—at the east end; while the west wall normally portrayed the Last Judgement as a symbol of our responsibility for our lives—a scene which followed and accompanied the faithful as they went out to resume their daily routine. As the iconography of the Last Judgement developed, however, more and more prominence was given to its ominous and frightening aspects, which obviously held more fascination for artists than the splendour of hope, often all too well concealed beneath the horrors.During the various discussions that have been happening on various 'blogs today, it's been pointed out that the Last Judgement is painted on the western wall of the Sistine Chapel. Now, it's not at all unusual for 'liturgical East' to be 'geographical West', I'm curious as to how it came about that the altar in the Sistine Chapel faces geographical west, towards something that iconographically belongs at the 'liturgical West'. Is there an interesting historical explanation?