The twenty years between the two World Wars — a period of democratic experimentation, fascist and communist revolution, economic catastrophe, and the failure of the international order created at Versailles — that ended with the most destructive war in human history.
The interwar period began with the most ambitious attempt to create a peaceful international order in modern history and ended with the most catastrophic failure of that attempt. Twenty years separated the Treaty of Versailles from the German invasion of Poland. Within that time, democracy collapsed across most of Europe, the global economy imploded, and the conditions for genocide and world war were assembled piece by piece.