Belgium, 1936 Zeppelin Olympic Flight. Airmail card originating from Belgium to Berlin franked with two Belgian stamps tied by "Bruxelles-Aeroport/31.VII.36" postmark in combination with German 50pf Zeppelin Airmail tied by "Frankfurt/Rhein-Main/1.8.36" postmarks with magenta Zeppelin Olympic flight cachet and "Berlin-Zentralflughafen/1.8.36" cds alongside, German adhesive with gum staining, Very Fine, a rare non-treaty combination usage. Estimate  $300 - 400. $0 (Image)