Operation Valkyrie
On 14 July Stauffenberg attended Hitler's conferences carrying a bomb in his briefcase, but because the conspirators had decided that Heinrich Himmler and Hermann Göring should be killed simultaneously if the planned mobilisation of Operation Valkyrie was to have a chance to succeed, he held back at the last minute because Himmler was not present. In fact, it was unusual for Himmler to attend military conferences.