World War II was the largest armed conflict in the history of mankind. It was attended by 62 states out of 73 that existed at that time (80% of the world's population). Fighting took place on three continents and in the waters of four oceans. This is the only conflict in which nuclear weapons have been used.
By 1939, as a result of the crisis and collapse of the Versailles-Washington system of international relations, two military-political blocs of great powers were formed, in which Great Britain and France opposed Germany and Italy, to which Japan gravitated. The USSR and the USA took a wait-and-see attitude, hoping to use the war between these blocks in their interests.
The military-political blocs that prevailed in Europe sought to achieve their own goals, which increased the risk of a war. The leadership of the USSR made efforts to avert the threat of being drawn into a possible European war. This war was supposed to weaken Germany, Great Britain and France, which, in turn, would allow the USSR to maximize its influence on the continent. For its part, Germany, realizing the impossibility of a simultaneous military conflict with a coalition of great powers, hoped to limit itself to a local operation against Poland, which would improve its strategic position for the further struggle for hegemony in Europe with Great Britain, France and the USSR. Italy sought to obtain new concessions from Britain and France as a result of their conflict with Germany, but it was in no hurry to enter the war. The United States needed a war in Europe to exclude the possibility of an Anglo-German alliance, to finally take England's place in the world and weaken the USSR, which would allow them to become the main world force. Japan, taking advantage of the involvement of the remaining great powers in Europe, intended to end the war in China on its own terms, to obtain consent from the United States to strengthen Japanese influence in the Far East and, under favorable conditions, to participate in the war against the USSR. So, as a result of the actions of all the main participants, the pre-war political crisis escalated into a war unleashed by Germany.
