Zeppelin Flight. 1933 (September 30 - October 4), 8th SAF cover from Koroko to Buenos Aires, mixed franking with Upper Volta of 18 stamps altogether, tied by Koroko ''7.SEP.33'' ds, Friedrichshafen ''30.9.33'' connection, violet confirmation marking at top left, Buenos Aires ''6.OCT.33'' arrival on the back, mostly VF and very rare, only a few known, Sieger #235, Est. $1,500-$2,000 (Image)