Operation Weserübung
Operation Weserübung (German: Unternehmen Weserübung [ˈveːzɐˌʔyːbʊŋ], transl. Operation Weser Exercise, 9 April – 10 June 1940) was the invasion of Denmark and Norway by Nazi Germany during World War II. It was the opening operation of the Norwegian Campaign. In the early morning of 9 April 1940 (Wesertag, "Weser Day"), German forces occupied Denmark and invaded Norway, ostensibly as a preventive manoeuvre against a planned Anglo-French occupation of Norway known as Plan R 4, which developed as a response to a German invasion of Norwegian territory.