1956, ISLAND COMMANDER GREENLAND DANISH C-in-C of GREENLAND Headquarters:Danish Naval Station Grondal A.P.O. 858 c/o Postmaster New York City N.Y. USA , violet cachet on airmail cover 23.11.56 franked with USA 15c. via A.P.O 858 to Vienna with arrival mark 4.12.56 on reverse.