On 1 September 1939, Nazi Germany invaded Poland, unleashing the Second World War. Adolf Hitler justified the attack with the staged “Gleiwitz incident,” a false-flag operation, and launched a war of aggression that would engulf the world.
At dawn, German forces stormed across the Polish border in a coordinated assault by land, sea, and air. It was the first demonstration of blitzkrieg– “lightning war”- combining fast-moving armoured divisions, mechanised infantry, and devastating air strikes. The Polish military, still reliant on horse-mounted cavalry in places, was quickly overwhelmed.
Britain and France, bound by treaty to defend Poland, declared war on Germany on 3 September. Yet their forces remained largely inactive on the Western Front during the so-called “Phoney War,” leaving Poland to fight alone.
Poland’s fate was sealed on 17 September when the Soviet Union invaded from the east under the secret terms of the Molotov-Ribbentrop Pact. Trapped between two totalitarian powers, Poland collapsed within weeks. Warsaw surrendered on 27 September after relentless bombardment, and by early October organised resistance had ended.
The consequences were catastrophic. Poland was partitioned between Germany and the Soviet Union. Millions of Polish citizens- including Jews, intellectuals and political leaders- were soon subjected to occupation, repression, and mass murder. Yet the Polish spirit endured: a government-in-exile was formed, and Polish forces would later fight alongside the Allies from the Battle of Britain to Monte Cassino.
The invasion of Poland marked the beginning of six years of global conflict that claimed an estimated 70–85 million lives, the deadliest war in history.
Also read: ON THIS DAY: Atomic bomb dropped on Hiroshima (1945)
For more videos and updates, check out our YouTube channel.