It's one of the unchallengeable 'truths' of the D-Day landings that the decision to wrong-foot the Nazis and invade Normandy rather than the Pas de Calais was a stroke of genius. But was it really? Yes, the Germans were waiting in force at Calais but a successful landing there would have captured a major port and opened the way to the conquest of France, the low countries and then Germany across the Rhine by the quickest, flattest and ultimately easiest route. The Brits in particular always over-estimated the actual German strength in France and, particularly, the English Channel. In reality there were only a few German planes available, about 300, no U-Boats and a few  E-Boats, fast motor boats firing torpedoes which had caused heavy casualties at a D-Day rehearsal a few weeks earlier in south Devon. But the Admiralty in particular was unwilling to risk its battleships in the Channel although the evidence from the Normandy landings was that the German air and naval threat was more or less non-existent and the heavy ships that were deployed caused much more damage with their accurate firepower than the more random heavy bombers. A couple of battleships off Calais with their 15-inch guns (and we had plenty left) would probably have made mincemeat of waiting German armoured divisions who had nowhere to hide in the flat fields of northern France. A D-Day attack on Calais may have led to more casualties on the day itself but it would have ended the war much more quickly.