German troops raise the German Navy’s ensign over Westerplatte after Polish troops surrendered on September 7, 1939. The Battle of Westerplatte, considered symbolic of Poland’s heroic stand against overwhelming odds, is commemorated by a historic monument. Photograph by Bundesarchiv, Bild 183-E10691
Sources used:
https://en.wikipedia.org/wiki/Battle_of_Westerplatte#
https://commons.wikimedia.org/wiki/File:Bundesarchiv_Bild_183-1989-516-505,_Westerplatte,_hissen_der_Reichskriegsflagge.jpg