Fill in the Blanks parrafo a completarOnline version para completar by Carmela Donis 1 service industrial widespread erasing more between capabilities eventually major opposing lasted state people placed known involved World War II ( WWII or WW2 ) , also as the Second World War , was a global war that from 1939 to 1945 . It the vast majority of the world's nations including all of the great powers ? forming two military alliances : the Allies and the Axis . It was the most war in history , with than 100 million serving in military units from over 30 different countries . In a of " total war " , the participants their entire economic , , and scientific at the of the war effort , the distinction civilian and military resources .