German troops move toward Poland in 1939

The transcript describes the events leading to the start of World War II, beginning with the Nazi Panzer divisions crossing into Poland. Hitler's threats over the free City of Danzig escalated from verbal warnings to military action, marking the beginning of the conflict. The German invasion of Poland was a pivotal moment that signaled the onset of the Second World War.

What was the significance of the Germans moving into Polish territory?

What event did the actions of the Germans mark?