At the height of WWII, a group of German officers hatched a plot to assassinate Hitler and seize control of the military command in order to end the war. The operation was code-named 'Valkyrie', for the emergency plan that was meant to be used in case of a revolt against the Nazi government. This plan had been modified by the conspirators to ensure their success, but for various reasons the plot failed when finally carried out on 20 July 1944