The dramatic defence of the Netherlands in May 1940 against the German invasion lasted only five days. It started with a massive German airborne landing in the capital west of the country and ended with a, for those days impressive, German air bombardment of the harbour-city of Rotterdam, devastating the city centre and shocking the Dutch supreme command. When hours later another major Dutch community was threatened with destruction from the air the Dutch supreme command decided to surrender. How was it possible that a flat, water-rich country was seized so quickly by only modest German forces?