The Treaty of Versailles, which was signed in 1919, imposed harsh penalties on Germany for its role in World War I. These penalties included the loss of territory, the payment of reparations, and the demilitarization of the German military. The treaty was widely resented by Germans, and many felt that it was unfair and unjust.
In the years following the war, Germany experienced a period of economic and political instability. The country was plagued by high unemployment, inflation, and social unrest. In 1933, Adolf Hitler and the Nazi Party came to power in Germany. Hitler promised to restore Germany to its former glory and to overturn the Treaty of Versailles.
In the years leading up to World War II, Hitler began to pursue a policy of aggressive expansionism. He began by remilitarizing the Rhineland in 1936. In 1938, he annexed Austria and the Sudetenland. In 1939, he invaded Czechoslovakia.
The invasion of Czechoslovakia was the final straw for Great Britain and France. They had already issued warnings to Hitler that they would not tolerate any further aggression. When Germany invaded Poland on September 1, 1939, Great Britain and France declared war on Germany.
The declaration of war by Great Britain and France was a significant turning point in World War II. It marked the beginning of a global conflict that would last for six years and cost the lives of millions of people.