The Nazi invasion of Poland.
They attacked Poland from the east to ensure that they received their fair share of territory
Alongside France, Britain gave Germany a time limit to stop their invasion, when no reply was received they declared war on Germany.
The German invasion of Poland... complements of THE DENNIS JONESGermany invading Polandthe German invasion of Poland
Poland
Mongol invasion of Poland happened in 1240.
Canada declared war on Germany on September 9, 1939, in response to Germany invasion of Poland.
The Invasion of Poland was from 1 September - 6 October 1939
I believe it's Blitzkrieg.
The Soviet Union also invaded Poland around the same time. Germany invaded Poland on September 1, 1939 from the West, and the Soviet Union invaded Poland on September 17th of the same year from the East.
Self-Sacrifice
The 1939 invasion of Poland caused Britain to declare war on Germany, which started WWII.