During World War II there was a military campaign that lasted 6 years.
The Battle of the Atlantic was the longest continuous military campaign in World War II , running from 1939 to the defeat of Germany in 1945 . World War II . The war continued primarily between the European Axis powers and the coalition of the United Kingdom and the British Commonwealth , with campaigns including the North Africa and East Africa campaigns , the aerial Battle of Britain , the Blitz bombing campaign , the Balkan Campaign as well as the long-running Battle of the Atlantic .