1931 (2 Oct) registered and flown cover from Leningrad to Berlin, from there to Colombia, with franking added in Bogota for further transmission to Cali, v.f., with appropriate transit and arrival pmks (Image)

Est.US$250

1935 Moscow-San Francisco, used on registered and flown cover (back restored, thus needs to be considered a coverfront) from Moscow to San Francisco, with bilingual "Special Air Flight Moscow-San Francisco through the North Pole" cachet, v.f. (three Soviet fliers, Sigismund Levanevsky, George Baidukov and Victor Levchenko, took off from Schlovsky Military Airport near Moscow in the red-winged Soviet monoplane "O 25" at 6:30 A.M. on a 6,000 mile non-stop flight to San Francisco, via the North Pole. Flying over Siberia and 700 miles across the Arctic Ocean, the plane developed problems, and on radio instructions, the fliers returned to their base) (Image)

Est.US$2,500