... if D-Day had failed, Stalin would have ended up occupying almost all of German, which would have significantly changed the balance of power in the Cold War. Had the Allies invaded France in 1943, rather than invading Sicily, they probably would have made faster progress than they did in 1944. VE Day would have come a year earlier, with the Allies capturing most of Germany.
My unending thanks to all the men and women who fought this day, and the entire war, in 1944. Via The Volokh Conspiracy » D-Day thoughts.