An effect of the Treaty of Versailles was that it helped created a situation in Germany which led to the rise of Adolf Hitler and the Nazis, thus setting the stage for a Second World War.
The Treaty of Versailles, which came out of the Paris Peace Conference in 1919, was very punitive towards Germany. Germany was forced to admit responsibility for causing the Great War (World War I). We now call that "the war guilt" clause of the treaty. Germany also was forced to pay large reparation payments to the Allies (who opposed Germany in the war). The German economy and national pride were deeply wounded. The Great Depression, which was worse in Germany than in America, complicated things even further. The bad situation in Germany made it possible for a radical leader like Hitler, making all sorts of bold promises, to win over enough people to rise to power. Hitler promised a return to national greatness and fiercely rebuilt Germany as a military machine. The rise of Hitler and the Nazis brought about World War II in Europe.
