(Main article: 20 July plot) On 20 July 1944, Adolf Hitler and his top military associates entered the briefing hut of the Wolf's Lair military headquarters, a series of concrete bunkers and shelters located deep in the forest East Prussia, not far from the epic World War I Battle of Tannenberg. Suddenly there was an enormous explosion, which killed three officers and a stenographer, and injured everyone else. This assassination attempt was the work of Colonel Claus von Stauffenberg, an aristocrat who had been severely wounded – losing his right hand, left eye, and two fingers of his left hand – while serving in the North African theater of war.