Large cover fr. with 1dr. grey in vertical strip of 5, overprinted with linear "ΥΠΟΥΡΓΕΙΟΝ ΕΞΩΤΕΡΙΚΟΝ" and posted from "ΑΘΗΝΑΙ*10 ΜΑΡΤ. 18.." to Greek consulate to Petersburg, arr. "PETERSBURG*17.3.88". THE LARGEST RATE UNTIL NOW ON COVER. UNIQUE. RRRR. (Hellas 69).