Secretly, Hitler had already told his military leaders to be ready for war.
And just a month after his trip to the Munich Art Festival,Hitler announced to his generals that they should harden their hearts against the enemy.
One general who wasn't part of Hitler's plans was Ludwig Beck.
He'd resigned as Chief Of Staff of the German army,believing now, as he said to a friend,that Hitler was a psychopath through and through.
He was more certain than ever that Hitler was leading Germany to catastrophe.
"I warned and warned," he said, "and at last I stood alone."
On 1st September 1939, the German army invaded Poland.
Two days later, Britain and France declared war on Germany.
The Polish army stood little chance.
Not only was this ideal country for the German tanks,but under a secret part of a non-aggression agreement with Stalin,signed just days before,
Germany and the Soviet Union split up Poland between them.
The Germans invaded Poland from the west.
Two weeks later, the Red Army invaded Poland from the east.
Less than six weeks after it began, the war was over.Poland was crushed.