March 21 in Military History — On This Day

German Spring Offensive (Operation Michael)

With Russia knocked out of the war, Germany transferred 50 divisions west for a last desperate gamble before American troops arrived in strength. Using stormtrooper infiltration tactics, they smashed through British lines, advancing up to 40 miles — more ground than anyone had taken in three years. Paris was shelled by a 75-mile-range gun. Then momentum stalled as supply lines couldn't keep up.

The greatest territorial gain on the Western Front since 1914. But Germany exhausted its best troops for limited strategic gain. The advance actually helped — it forced the Allies to finally unify command under Marshal Foch. With American divisions arriving monthly, Germany had burned its last reserves.

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⚔️📍 Somme, France1918

Operation Michael — Germany's Spring Offensive Begins

Germany launched its last great offensive of WWI with a 5-hour artillery bombardment of unprecedented intensity, followed by elite stormtrooper units using new infiltration tactics. British lines broke and German forces advanced further in one day than in any offensive since 1914.

The Spring Offensive came close to splitting the British and French armies and forcing a catastrophic retreat but ultimately exhausted Germany's last offensive reserves.

Outcome

Initial German breakthrough; advance halted by August

Casualties

500,000