abstract:Nacht und Nebel (German for "Night and Fog" – a direct reference to a "Tarnhelm" spell, from Wagner's Rheingold) was a directive () of Adolf Hitler on 7 December 1941 that was originally intended to winnow out all political activists and resistance 'helpers', "anyone endangering German security" (die deutsche Sicherheit gefährden) throughout Nazi Germany's occupied territories. Two months later Armed Forces High Command Feldmarschall Wilhelm Keitel expanded it to include all persons in occupied countries who had been taken into custody and were still alive eight days later.