The twentieth century saw a remarkable shift in the way that vast numbers of people lived, as a result of technological, medical, social, ideological, and political innovations. Terms like ideology, world war, genocide, and nuclear war entered common usage and became an influence on the lives of everyday people. War reached an unprecedented scale and level of sophistication; in the Second World War (1939-1945) alone, approximately 57 million people died, mainly due to massive improvements in weaponry.