History & Civics
Answer
On 7 May 1915, a German U-boat torpedoed and sank the RMS Lusitania, a British ocean liner en route from New York to Liverpool, Britain. It contained many passengers and about 1,100 of the 1,900 passengers and crew members on board perished, including 128 Americans. The USA was outraged and entered the war on 6 April 1917.