World War I which began in Europe in July 1914 soon engulfed almost the entire world. The damage caused by this war had no precedent in history. In the earlier wars, the civilian populations were not generally involved and the casualties were generally confined to the warring armies. The war which began in 1914 was a total war in which all the resources of the warring states were mobilized. It affected the economy of the entire world and the casualties suffered by the civilian population from bombing of the civilian areas and the famines and epidemics, caused by the war far exceeded those suffered by the armies. In its impact also, the war had no precedent. It marked a turning point in world history. The battles of the war were fought in Europe, Asia, Africa and the Pacific. The geographic boundaries were redrawn. Power centers changed. Because of the unprecedented extent of its spread and its total nature, it is known as the First World War.
The intense imperialist rivalry among European and formation of military alliances (Triple entente -England Russia France in 1907 and triple alliance pledging – Germany, Austria and Italy -1882) along with secret alliances, militarism, and nationalism resulted in outbreak of WW I in 1914 – Assassination of Austrian Heir Archduke Francis was immediate cause of outbreak
Consequences of WW I included
Around 9 million soldiers died in battle. Civilian loss of life totaled an additional 13 million. Epidemics of influenza and other diseases, either induced or exacerbated by the war, raised the death toll by at least an additional 20 million. In total, counting battle casualties, civilian deaths, and victims of disease, the loss of life worldwide surpassed 40 million harsh and humiliation treatment to Germany in the form of signing Treaty of Versailles, by the end of the war, four major imperial powers—the German, Russian, Austro-Hungarian and Ottoman empires—ceased to exist, defeated powers lost their colonies, major territorial changes in Europe, independence of Hungary and setting up of League of Nation by Woodrow Wilson.