By July 1940, it became clear to the British that they were not going to return to the continent anytime soon, and began to organize intelligence units to support partisans around occupied Europe. Called Special Operations Executive (SOE), it organized espionage and sabotage operations, supplied and trained guerilla units, and was the model for the US Office of Strategic Services.
When Czech SOE agents killed SS Chief of the Reich Central Security Office (RSHA) Reinhard Heydrich in 1942, the Germans destroyed the town of Lidice, Czechoslovakia on June 10, 1942. The men were shot, the woman and children deported, and the town blown up and covered over. The name was removed from all German maps.
The effectiveness of resistance varied by country. In Germany, resistance movements were largely ineffective and were eliminated before the war. The best known is the Weisse Rose (White Rose) which was their password. Two University of Munich students, brother and sister Hans and Sophie Scholl, organized students and soldiers opposed to the Reich in 1942. One soldier had seen the Einsatzgruppen (Action Groups) that shot Jews on the Eastern Front. In February 1943, they dropped leaflets critical of Hitler that said “Germany’s name will be disgraced forever,” from their University’s window. Both were arrested, tortured, and sentenced to death. Sophie, her leg broken by the Gestapo, was beheaded.
But most Germans were supportive of the Nazi Regime and loyal to Hitler. When the Allied armies approached the Rhine in 1945, the lack of the effective resistance that guided the Allies in France was deeply felt.
In France the resistance was well organized by the end of 1940. They fought two set-piece battles with German troops, rescued hundreds of Allied pilots, and sabotaged many trains and bridges. Their effectiveness has been overstated in the popular media, but they did hold divisions that would have made a difference on the Eastern Front. The Communist partisans in Paris rose up and fought the Germans as the Allies approached in August 1944.