The Paleochristian and Byzantine Monuments of Thessalonika are a group of religious monuments known for their mosaics and distinct architectural typology.Thessaloniki is Greece's second largest city, situated in the northeast, in Macedonia prefecture. During its heydays, in the Byzantine period, it was also the empire's second city (to Constantinople, in that case). Thessaloniki derives its name from the first daughter of King Philip of Macedon. She married Kassandros, Alexander the Great's