Nazi Germany launched a coordinated land-and-air assault on Poland, inaugurating the Blitzkrieg style of rapid, combined-arms warfare and triggering the broader European war.
The German attack on the Polish Military Transit Depot at Westerplatte became an early symbol of Polish resistance and is widely cited among the first battles of the invasion.
After Germany’s invasion of Poland, the United Kingdom and France declared war, transforming the conflict into a general European war even as major fighting in the west initially remained limited.
France’s limited advance into the Saar region (and subsequent withdrawal) underscored the strategic stalemate in the west while Poland was being defeated.
Poland’s largest counterattack of the campaign briefly disrupted German momentum near Warsaw but was ultimately defeated by German maneuver and air superiority.
In line with the Molotov–Ribbentrop Pact’s division of spheres, the USSR entered Poland from the east, sealing Poland’s strategic predicament between two invading powers.
The defeat of Polish forces near Kock marked the end of the last major regular-unit resistance in the 1939 campaign, concluding Germany’s conquest phase in Poland.
Germany attacked Denmark and Norway to secure strategic positions and supply routes (notably for Swedish iron ore), expanding Blitzkrieg-style operations beyond Poland.
Germany launched its western offensive into the Netherlands, Belgium, and Luxembourg, outflanking French defenses and initiating the rapid collapse of the Allied front.
A surprise glider-borne attack neutralized a key Belgian fortress guarding Albert Canal crossings, demonstrating the shock effect of German airborne tactics in 1940.
The Luftwaffe’s bombing of Rotterdam helped break Dutch resistance; Germany also threatened further destruction, and the Netherlands capitulated shortly thereafter.
With Allied forces trapped, Britain initiated a large-scale sea evacuation from Dunkirk, preserving the core of the British Expeditionary Force and many French troops for continued resistance.
After heavy fighting, Belgian forces capitulated, tightening the German encirclement pressure on Allied armies in northern France and accelerating the crisis that led to Dunkirk.
The operation ended after evacuating roughly 340,000 Allied personnel, a major strategic and morale turning point despite the loss of equipment and France’s worsening position.
Mussolini declared war as France’s defeat appeared imminent, expanding the conflict and opening a new front during the closing phase of the 1940 western campaign.
German troops entered and occupied Paris after the French government declared it an open city, symbolizing the collapse of organized French defense in the north.
France and Germany signed an armistice that created a German occupation zone over much of northern and western France; it took effect several days later, formalizing France’s defeat.
German Blitzkrieg Campaigns in Poland and Western Europe (1939–1940)
