Russia, 1935, Mi. 527 1 ₽ - Russian ruble  on 10k, Moscow-San Francisco via North Pole Flight - Surcharge & overprinted in red - ' Перелет Москва— 1Р. Сан–Франциско через Сев. полюс 1935 '. Superb fresh Mi:SU 527, Sn:SU C68, Yt:SU PA59, Sg:SU 706 cat €1,100 OG  VF++