What Caused the First World War?

The first world war was caused by a series of events that took place between Austria-Hungary and Sibera. First Austria-Hungary annexed a portion of the country from the land. Then the Siberian nationalist leader staged an assasination of Archduke Franz Ferdinand as a threat to the country, because he wanted that nation for Siberia. Eventually countries in Europe, as well as the United States formed alliances with one another and the war began.