British ocean liner RMS Lusitania was sunk by a German U-boat on the 7th of May, 1915, less than a year into the First World War. 1198 out of 1959 people aboard were killed, and the sinking played a big hand in turning international opinion against Germany.
This propaganda poster was released in Britain the same year, in an attempt to recruit men into the Leicestershire Regiment (now the Royal Leicestershire Regiment).
In Times Gone By... 