Nationalism in the Twentieth Century In the world of the twentieth century, there was a growing shift toward a sense of nationalism in many countries around the world. There was a big change in this time due to the changes made during the two world wars and the effects of what happened after them. If we look at the world between the end of World War I and the end of World War II, we see an immediate difference between the two worlds. From 1919 to 1945, there was a difference not only in the way people acted, but also in the way situations were handled between different countries. Relations between the countries were different from 1919 to 1945 because many leaders of each country had different feelings at the end of each war. If we look at the 20th century and the differences from 1919 to 1945, there was a big difference between the two worlds. . After World War I, relations between the two countries were neither good nor bad. There was not much resentment after World War I, and the problems that caused the war were largely resolved. Germany was the only country still truly bitter about the outcome of the First World War. After the First World War, there was what historians have called the interwar period. It was the period from 1918 to 1939 and it was the period between the two world wars. During this period, many advances took place, not only in the military field but also in the economies of different countries. During this period, the United States went through a decade in the 1920s and then a terrible depression. During this period, the British faced uprisings in their various colonies and landholdings across the world. They made people give up their total protection and get their own forms of parliaments and lost men fighting and dealing with the various uprisings in Ireland and Kenya.,