The war came in August of that year, but it did not work out as planned. It lasted four years. The total number of military deaths is estimated at 9 to 11 million. The civilian death toll is about 8 million. The total number of casualties—dead, wounded, and missing—military and civilian, is probably 40 million. The heads of state had not factored in the machine gun, rapid-firing artillery, chlorine, phosgene, and mustard gas, radio, tanks, airplanes, barbed wire, smokeless powder, or flamethrowers. The generals and the field marshals were clueless. The British alone took 60,000 casualties on the first day of the Battle of the Somme.