W orld W ar II was a global war that lasted fr om 1939 to 1945 and inv olved the majorityof the world' s nationsincluding all of the gr eat powerseventually forming twoopposing militar y alliances: the Allies and the Axis. It was the most widespr ead war inhist ory, and dir ectly inv olved mor e than 100 million people fr om more than 30 countries.In a state of "t otal war", the major par ticipants threw their entir e economic, industrial,and scientic capabilities behind the war effor t, erasing the distinction between civilianand militar y resour ces. Mark ed by mass deaths of civilians, including the Holocaust (inwhich appr oximately 11 million people wer e killed) and the strategic bombing ofindustrial and population centers (in which appr oximately one million people wer ekilled), it r esulted in 50 million t o over 70 million fatalities.The war in E urope began with the inv asion of Poland by Germany and the So viet Union,followed b y the British and F rench declar ation of war on Germany in September 1939.F rom late 1939 t o early 1941, in a series of campaigns and tr eaties, Germany conqueredor contr olled