During the First World War, specifically, in 1917, the war led to the Russian Revolution which put the Bolsheviks in power. As a result, Russia was forced to withdraw from the war, leading to a significant loss of land.
In Eastern Europe, strong national identities rose, exemplified by Serbian nationalist Gavrilo Princip shooting Archduke Franz Ferdinand. Serbian nationalism vs. Austro-Hungarian opposition was one of the main causes of the war.
The war led to the end of the Ottoman Empire, leading to the formation of several different states, such as Turkey, Syria, Iraq, Transjordan, and Palestine. However, Great Britain made promises to both the Arabs and Palestine, leading to conflicting issues in regard to keeping those promises.
The industrialization that occurred in the United States led to the emergence of them as a global power; however, after the successes of the war, the Great Depression occurred. As a result, FDR implemented his "New Deal" which sought economic reform.
Latin American governments began to move countries away from an earlier dependence on exports, and instead created their own goods. This process, called import substitution industrialization, was dome by authoritarian governments which imposed high tariffs and favored state-run industries.
Because of the Great Depression, countries in Scandinavia along with Britain and France implemented a new economic system of democratic socialism, which called for government economic regulation and a significant redistribution of wealth.