On May 20 1915 a German submarine torpedoed what British passenger liner?

On May 20, 1915, the German submarine U-20 torpedoed the British passenger liner RMS Lusitania. The attack occurred off the coast of Ireland, resulting in the sinking of the ship and the loss of nearly 1,200 lives, including many American citizens. This event contributed to rising tensions between Germany and the United States during World War I.