In December 1941, the situation for the German troops both in Russia and in North Africa was difficult. Thus, when news about the Japanese successfull action at Pearl Harbor reached Hitler in his headquarter in East Prussia, he was delighted. After his military entourage had toasted on the ally, Hitler asked: "Where is that Pearl Harbor?"
None of the men knew it.
(Quoted from an American historian who himself quotes a German one, details on request).