Poland suffered more than any other country in World War 2, one in six Poles died in the hands of the Nazi occupiers, and the Jewish population was wiped out.
But Poland was only the trigger for a war which in two years was to engulf the world.
The programme examines why Hitler called off the invasion of Britain and turned to the Soviet Union, and why he declared war on the USA in the winter of 1941.
It ties together the separate strands of the series and tells how a local conflict developed into a global war.
