Blitzkrieg tactics explained | How Hitler invaded France WW2 In 1940, Hitler did the seemingly impossible. Within a matter of weeks, Germany had managed to take the entirety of France and send the British army back across the channel. This remarkable success was widely put down to their new tactic: Blitzkrieg or 'Lightning War'. So, what is Blitzkrieg and why was it so effective? Why the Dunkirk Evacuations were so successful: • How did the British escape from Dunkirk? Why Blitzkrieg didn't work