![How German U-Boats Were Used in WWI—And Perfected in WWII](https://ic-cdn.flipboard.com/history.com/fa14c6b398ccd308acd02fb2cbb57490225052b4/_xlarge.jpeg)
After terrorizing trans-Atlantic ships in World War I, German U-boats grew even more fearsome in World War II. The most formidable naval weapons in …
* View the article originally published here. ** More curations: Al Cannistra at San Antonio ONE here.