Global Military Conflict

World War II, was a global military conflict lasting from 1939 to 1945, which involved most of the world's nations, including all of the great powers: eventually forming two opposing military alliances, the Allies and the Axis. It was the most widespread war in history, with more than 100 million military personnel mobilized. In a state of "total war", the major participants placed their entire economic, industrial, and scientific capabilities at the service of the war effort, erasing the distinction between civilian and military resources. Marked by significant events involving the mass death of civilians, including the Holocaust and the only use of nuclear weapons in warfare, it was the deadliest conflict in human history, resulting in 50 million to over 70 million fatalities.
Germany and Italy lent support to the Nationalist insurrection led by General Francisco Franco in Spain. The Soviet Union supported the existing government, the Spanish Republic which showed leftist tendencies. Both sides used this war as an opportunity to test improved weapons and tactics. The Bombing of Guernica, a city of 5000 - 7000 inhabitants, was considered a horrifying attack at the time, with a propaganda figure of 1,654 people killed widely circulated in the west, leading to charges of "terror bombs”. In reality the attack was tactical operation against a city with militarily important communications close to the front-line, and modern estimates yield no more than 300 - 400 dead at the high-end.
Germany and Italy were becoming bolder. In March 1938, Germany annexed Austria, again provoking little response from other European powers. Encouraged, Hitler began pressing German claims on the Sudetenland, an area of Czechoslovakia with a predominantly ethnic German population; and soon France and Britain conceded this territory to him, against the wishes of the Czechoslovak government, in exchange for a promise of no further territorial demands. Soon after that, however, Germany and...