Introduction

World War II was a global military conflict that involved the world's most powerful nations and their confederates in two opposing military alliances, called the Allies and the Axis. The United States (US), United Kingdom (UK), The Union of Soviet Socialist Republics (USSR or "Russia"), Canada, Australia and China provided most of the fighting resources as Allies, while Germany, Japan, and Italy did the same as the Axis. Other European countries, such as Finland, Norway, Yugoslavia, Hungary, and France, also contributed to the war for one or the other alliance. (In the case of France, both sides.), while Spain, Sweden, Switzerland and Ireland remained neutral. Most South and Central American countries sided with the Allies. Colonies of the Allies and Axis also were involved in the war.

Over 100 million military personnel and about half of their economies were mobilized to fight the war on land, sea, and air, thus making it the most intense and widespread war in history. Some 60 million military and civilians died of various causes, making the war the deadliest in history.