In May 1940 France fielded millions of men, more than 3,000 tanks, British backing, and the most formidable fortification ever built. Six weeks later the nation had collapsed. This episode examines the intellectual, institutional, and psychological failures behind the Battle of France, starting with the trauma of 1.4 million dead in World War I that drove the Maginot Line strategy of funneling any German attack into Belgium, and the fatal assumption by Gamelin and Petain that the Ardennes would bottleneck a mechanized army.

We trace the eight-month Phony War, the Mechelen incident in which crashed invasion plans pushed Germany toward the Manstein Plan, and the May 10 trap that drew the best Allied armies north while Guderian's panzers broke through at Sedan. We cover the panic at Bulson, radio-coordinated Stuka support, French tanks spread  ...