The German submarine U-20 sank the RMS Lusitania on May 7, 1915, a British ocean liner, resulting in the tragic loss of 1,198 lives, including 128 Americans. This event dramatically escalated tensions between Germany and the Allied powers, particularly influencing the United States’ public opinion and hastening its entry into World War I two years later. The sinking of the Lusitania remains a poignant reminder of the perils of naval warfare and its impact on civilian life, shaping international maritime laws and wartime conduct.