Other mistake: In the opening scene of this German movie from 1944, a panoramic view of the city of Potsdam is shown with the subtitle "Potsdam 1813". In the background, the two high radio masts of the Potsdam Military Communication Central can be seen very clearly before the sky.
Other mistake: In the flashback of the denouement, Dr. Armstrong is shown dead face down on the beach, with the feet pointed ashore and the head to the sea. Mr. Owen takes also a sip from that Armstrong's flask and tosses it in the sand without capping it. However, Vera and Lombard found a corpse face inland and feet to the sea, and a flask with its lid in place. (01:28:50 - 01:34:40)