Aircraft of the Berlin - Königsberg - Moscow airline at the historic Devau airport in Königsberg, East Prussia, now Kaliningrad in the Russian exclave of that name. Deruluft was 50% owned by the Soviet government and 50% by Lufthansa, and this plane became D-1451 of Lufthansa in July 1928, but went back to Deruluft later. D-1079, the other Do B Merkur on the left, was operated by Deruluft from May 1927 until June 1928 under this German registration. Photo from: Lufthansa