By now I've experienced this several times; a story in WW1 or WW2 that's large and seems rather important, yet I've never heard of it before, and few others see

By now I've experienced this several times; a story in WW1 or WW2 that's large and seems rather important, yet I've never heard of it before, and few others seem to have as well [1]. N.b. I'm German and we probably have the most thorough history lessons on Nazism and the World Wars, yet both of these conflicts seem to be so vast that there is always another "big thing" one didn't know about yet. (However, for history lessons there is also the consideration that specific military engagements are not all that important, since German history teaching has a strong emphasis on motives and reasons why things happened and how they developed (it is very analytical that way); battles and other engagements and their outcomes are usually discussed as a result of the former, or the outcome of a battle is used as a starting point.). [1] U-Boat war? Sure, that was in the Atlantic, no? — Yes, but not only...