Hitler didn't just invade Poland — Stalin did too, two weeks later, under a secret deal that split the country between them before the first shot was fired.
On September 1, 1939, Germany launched a massive coordinated assault on Poland using Blitzkrieg — combining fast-moving tanks, motorized infantry, and close air support to overwhelm Polish defenses before they could organize a response. Over 1.5 million German troops crossed the border that morning.
Germany justified the invasion with a staged false flag operation called Gleiwitz: SS soldiers dressed in Polish uniforms faked an attack on a German radio station, broadcast a message in Polish, and left a dead concentration camp prisoner as supposed evidence of Polish aggression.
Poland was not just fighting Germany. On September 17, the Soviet Union invaded from the east under a secret protocol hidden in the Molotov-Ribbentrop Pact — a non-aggression treaty signed just nine days before the war began that secretly divided Eastern Europe between the two powers.
Despite being heavily outnumbered, Polish forces fought fiercely and inflicted real losses — over 16,000 German soldiers were killed and nearly 700 aircraft destroyed. The famous image of Polish cavalry charging tanks is largely myth: they used horses for mobility and dismounted to fight.
The Polish government and military fled through Romania into exile, eventually establishing a government-in-exile in London. Polish airmen, soldiers, and sailors who escaped would go on to fight across Europe — some of the most motivated combatants of the entire war.
Warsaw endured weeks of bombing and artillery before surrendering on September 27. The Luftwaffe's deliberate targeting of civilian areas was an early signal of the brutal character this war would take. Over 25,000 Polish civilians died in the siege of the capital alone.
The fall of Poland handed Germany access to vast eastern resources and eliminated the threat of a two-front war — at least until Germany turned on its Soviet partner two years later. Stalin, meanwhile, gained the buffer zone he had long coveted along his western border.