Alright, so you know that the Treaty of Versailles was a 1919 peace-treaty between several countries created after World War I. Most of its terms were specifically thrown at Germany, with the Allies punishing Germany in a way that they would never start a war again.
As a result of the Treaty, the German people were absolutely furious. They resented the Allies more than anything else, and felt that they were being punished unfairly. Germany was a major wreck after the Great War, and these terms made the country's conditions even worse. In fact, it was the Treaty of Versailles that made people like Hitler rise up to glory. He used the Germans' anger and resent of the Allies to gain more power, and eventually the German people would give in, leading to World War II.
