Up for auction is a beautiful airmail Real Picture Postcard cover RPPC from, Germany to Copenhagen Denmark mailed on the Graf Zeppelin airship LZ 127 Baltic Sea flight.  Priced to sell. Postmarked in May 12, 1931.  . Cover is in excellent condition. Great cancels and markings. Good zeppelin markings. Stunning of # C38 stamp with a catalogue Value of $400.000 .