1940
Battle of Sedan (1940)
The setting
Sedan and the Meuse River, northeastern France
The Meuse river line near Sedan, on the southern edge of the wooded, hilly Ardennes that the French high command had judged unsuitable for large armored forces; the river was the main defensive barrier, held by second-line French infantry divisions.
Reveal the outcome
Recorded sideGermany (XIX Panzer Corps under Guderian, Army Group A)
Recorded resultDecisive victory; Meuse crossed and bridgehead broken open
German armored forces crossed the Meuse at Sedan and broke through the French line, enabling the rapid drive to the English Channel. (Manstein planned the overall Ardennes thrust; Guderian led the breakthrough corps.)
How the atlas explains it
A surprise main effort through the Ardennes struck a weakly held sector; concentrated dive-bomber and air support, radio-coordinated panzers, and aggressive combined-arms river crossing broke the morale of second-rate French divisions before they could organize, and the breakthrough was exploited faster than the French could react.
What followed
The decisive breakthrough of the 1940 campaign: it unhinged the Allied front, enabled the drive to the Channel that trapped Allied armies (leading to Dunkirk), and led to the fall of France within weeks.