Latvia. May 28-31, 1933, Latvia - Africa Attempted Flight cover from Riga, addressed to Norway, franked by six air post values, including three bearing ''Latvia-Africa. 1933'' overprint, due to airplane crash in Germany correspondence were delivered by other flights or surface mail, Berlin ''31.5.33'' transit and Oslo ''1.VI.33'' arrival ds, VF, C. Ceremuga certificate, Est. $250-$300 (Image)