It’s complicated to determine when the world war two started exactly depending on where you reading and from which perspective the historian is writing from. Some would argue that it started in September 1939 when Germany invaded Poland. Others would argue that it started in 1933 when Hitler took over the power in Germany. Another argument would be that it started in 1937 when the Japanese invaded China because the war between those two parties ended in 1945. The last argument which I personally lean more into is that the world war two actually started in 1931 when Japan Invaded Manchuria since from there everything evolved and leaded to the world war two.
There was a global involvement in the world war two which is the reason why the war was granted the name “world war two” and those countries are divided into different categories, there was two categories that were pro-invading and starting the war, The First category is “The Axis Powers” which are the countries who signed the Tripartite Treaty, and they are: Germany, Italy, and Japan. The Second category is “The Co-signers of the Tripartite Treaty” and they are: Bulgaria, Hungary, Romania, and Slovakia.
On the other side of the war, there were three different categories, the first category was “Countries that were annexed by, or at war with, Axis Powers before the World War II”, which are: China, Australia, Ethiopia. The second category was the “Allied Powers” which are the following countries: Australia, Brazil, Canada, Newfoundland, New Zealand, South Africa, Soviet Union, United Kingdom, United States. The third category is “Supporters of the Allies” which include the following: Argentina, Bolivia, Chile, Colombia, Costa Rica, Cuba, Dominican Republic, Ecuador, Egypt(2), El Salvador, Guatemala, Haiti, Honduras, Iraq, Lebanon, Liberia, Mexico, Mongolia, Nicaragua, Panama, Paraguay, Peru, Saudi Arabia, Turkey, Uruguay, Venezuela.
The progress of the war was shifting between both sides, that progress was translated in occupying or attacking countries who are In most cases were the battle field of war world two. And that increased the number of countries which were involved in that massive war, First Germany attacked and occupied the following countries: Albania, Belgium, Czechoslovakia, Denmark, Estonia, France, Greece, Lativa, Lithuania, Luxembourg, Netherlands, Norway, Poland, Yougoslavia. Secondly Italy occupied and attacked the following countries: Albania, Greece. And thirdly, the Soviet Union attacked: Estonia, Finland Lativa, Lithuania, Poland. Fourthly, the United State of America occupied Denmark, Tunisia and Iceland.
The fighting between Japan and China was brutal, brutal enough to actually effect the relationship between those two countries up until today, but the world war two that we are all know more about is the one in the European sector of the world, where Hitler took power and started giving the revolutionary promises to germens to return the homeland to its former glory, in the beginning it was introduced as a new style of combat using technology and air force to protect the troops on land, which was a very effective method back then and The Nazis were able to roll over Poland, Norway, Denmark, the Netherlands, and then all of France. Until they were in control of most of central Europe, where they began to set the great Britain as a goal. Meanwhile, Europeans were also fighting each other in North Africa. In 1941 the Nazis invaded Russia breaking a non-aggression pact that the two powers had signed in 1939, in the same year of 1941 the Japanese bombed Pearl Harbor which helped in creating alliance between great powers and eventually leaded to the end of war world two with massive destruction and high rate of death between all sides involved.
Source: BBC, TEAM. "World War Two: Summary Outline of Key Events." 30 3 2011: n. page. Web. 30 Aug. 2013 <http://www.bbc.co.uk/history/worldwars/wwtwo/ww2_summary_01.shtml>. History, Channel. "US ENTRY & ALLIANCE." 23 3 2010: n. page. Web. 30 Aug. 2013. <http://www.history.co.uk/explore-history/ww2/us-entry-and-alliance.html>.