How did the Treaty of Versailles contribute to the rise of Hitler in Germany?
The punitive nature of the Treaty of Versailles directly led to the economic conditions that allowed for a demagogue such as Hitler to gain support. First, the so-called Guilt Clause, which forced Germany to claim full responsibility for starting World War One -- when in fact it was a war of multi-lateral aggression -- eviscerated the pride of the German people.
Second, the imposition of trillions of dollars in "war reparations" that the already cash-starved German state was supposed to pay back to the victors drove Germany's economy to collapse, created unprecedented inflation not seen again until modern-day Zimbabwe, and led millions of Germans to acts of unbelievable desperation in order to avoid starvation.
On top of that, the Treaty of Versailles allowed for the Allied occupation of Germany's most productive land (the Rhineland and Sudetenland), and gave disputed territory like Alsace-Lorraine back to the French. The effect of the Treaty was to impoverish and humiliate the German people, create riots in the streets, and leave the government unable to meet its basic obligations, like preserving law and order and providing basic social services.
In that vacuum of power, both the far left (Communists) and the far right (National Socialists, who became known as the Nazis) gained support and raised well armed militias. Hitler and other Nazi leaders promised a return to greatness, assuaged German humiliation by blaming the loss of the war on socialists and Jews who had "stabbed Germany in the back," and promised that a new social order would restore Germany's economy by confiscating property and money from "undesirable races" that had, according to Hitler, leeched off Germany for centuries.
Had Germany not been punished so severely or been made to take full responsibility for a war that everyone in Europe was responsible for starting, the conditions under which Hitler thrived would simply not have existed. In hindsight, the Treaty of Versailles looks almost like a playbook for the creation of a demagogue.