"My heart is in the east (mizrach) and I am at the end of the west." So lamented Yehuda Halevi, the greatest medieval Jewish poet. Halevi was referring not only to his yearning to leave Andalusia and return to Zion but also to the halachic requirement to face Israel while praying.
This is taught by the Talmud (Berachot 30a), which tells us that those praying outside of Israel should face Israel; those in Israel should face Jerusalem; those in Jerusalem should face the Temple; those in the Temple should face the holy of holies. The Talmud describes Jerusalem as a "hill toward which all mouths are turned".
The Rema (16th-century Poland) comments that one should not place the synagogue ark directly in the east, for it might look as though we were worshipping the sun. (Southeast is preferable, and geographically more accurate if you are in Poland.)
Beautiful mizrach signs for home and synagogue have survived the centuries. They bear witness to the yearning for Zion that was a unifying force throughout the ages.