RMS Lusitania was a British-registered ocean liner that was torpedoed by an Imperial German Navy U-boat during the First World War on 7 May 1915, about 11 nautical miles (20 km; 13 mi) off the Old Head of Kinsale, Ireland. The attack took place in the declared maritime war-zone around the United Kingdom, three months after unrestricted submarine warfare against the ships of the United Kingdom had been announced by Germany following the Allied powers' implementation of a naval blockade against it and the other Central Powers.
The passengers had been notified before departing New York of the general danger of voyaging into the area in a British ship, but the attack itself came without warning. From a submerged position 700 m (2,300 ft) to starboard, U-20 commanded by Kapitänleutnant Walther Schwieger launched a single torpedo at the Cunard liner. After the torpedo struck, a second explosion occurred inside the ship, which then sank in only 18 minutes. U-20's mission was to torpedo warships and liners in Lusitania's area of operation. In the end, there were only 763 survivors (39%) out of the 1,960 passengers, crew and stowaways aboard, and about 128 of the dead were American citizens. The sinking turned public opinion in many countries against Germany. It also contributed to the American entry into the war almost two years later, on 6 April 1917; images of the stricken liner were used heavily in US propaganda and military recruiting campaigns.
