1971 illustrated postal cards (Thessaloniki issue), complete set of 6 postal cards cac. "ΤΑΧ.ΓΡΑΦΕΙΟΝ ΔΙΕΘΝΟΥΣ ΕΚΘΕΣΕΩΣ ΘΕΣΣΑΛΟΝΙΚΗΣ*29.ΑΥΓ.1971" (first day of issue). (Hellas PC66(1-3)+PC67(1-3)).