Nationalism heightened in the 19th century and heading into the 20th century. The nationalistic fervor by people in Europe had them each viewing their own nations as better than the others, in competition with the others. This would lead to an increase in tension between the nations.
Imperialism expanded on that nationalistic rivalry by carrying their competition to other parts of the globe. The nations of Europe sought to grab control for themselves over parts of Asia and Africa. When war erupted, that also meant it would become a world war because the European nations would include people from their imperial territories in the war.
Militarism grew ever more potent as the 20th century opened. The competition between nations included a massive arms race in terms of expanding armies and navies. The nations also sided up in competing military alliances and made military battle plans as to how they might fight a war if war came. When a cause for war broke out, all those preparations propelled the nations of Europe into war recklessly.
James I of England angered many of his subjects by "<span>d. returning the land taken from Irish Catholics by Elizabeth I" this this was a contested issue.</span>
Poverty spread during the Great Depression, because of skyrocketing prices of needed things, which led to people not being able to take care of themselves
hope this helps
To bring justice to the remaining nazi leaders after the war and to show the power of the allies and the soviet union
