World War 1 Edit
World war 1 started with the assassination of Franz Ferdinand of Austria-Hungary. His death was at the hands of Gavrilo Princip a serbian nationalist secretive military group known as Black Hand-propelled major European military powers towards war. The first world war gave the US their 1st tanks, chemical warfare, guide dogs, gas masks, x-ray machines, flame throwers, steel helmets, fleets of fighting aircraft, aircraft carriers, established blood bank, enlisted women, Navy's yeomanettes, soldiers IQ tests, presidential trip to Europe, Woodrow wilson attended paris peace conference, and finally only war to be commonly called the war to end all wars.
World War 2 Edit
World war 2 started by Germany in an unprovoked attack on Poland. It contained many of the world's countries. Europe began on 3rd September 1939 when Prime Minister of Britain, Neville Chamberlain.
If japan had never bombed pearl harbor america may never have had a 2nd ww. There only would have been France, Germany, and Great Britain in a second ww.
http://www.history.com/topics/world-war-ii/world-war-ii-history Goes to bottom article
World War 3 Edit
5 places war could start this year Korean Peninsula, cyberspace, Syria, South Asia, and Baltic Sea.
North Korea could start a third ww so the leader can avoid collapse of hermit state. Kim Jung-un could launch a world war 3 to distract from starvation in his hermit state.