On May 7th 1915, the British ocean liner RMS Lusitania was sunk by a German submarine. The sinking of Lusitania and the loss of nearly 1,200 civilian lives caused an international outcry. Germany argued that the ship was a legitimate military target as it was carrying ammunition and military goods and travelling through what was declared a 'war zone'. Right or wrong, read more about Lusitania, the events on May 7th, and the aftermath in Wikipedia. You can find Lusitania pictures and stories shared by archives and private contributors in the Great War Archive, First World War Poetry Digital Archive and Europeana 1914-1918 collections.