20 July 1944,
German officer Klaus von Stauffenberg tried to kill Hitler. At Hitler's headquarters in eastern Prussia, he caused the bomb's headquarters during an information conference with the officers. After the attack the Nazi regime and II are dissolved. There was a German resistance group seeking to negotiate the end of the World War. As a result of the failure of the trial, Stauffenberg himself and other conspirators were executed.
Source:
Joachim Fest, Plotting Hitler’s Death: The German Resistance to Hitler, 1933-1945 (Orion).