Why is d-day considered a major turning point of world war ii?

During the Blitzkrieg, Germany forced all Allied troops out of France. Because of a long time between the Fall of France and D-Day, Germany was able to be Prepared. Due to the Planning and equipment and skill of the Allied forces, they were able to make a successful naval invasion of France. This Led to the Retaking of France, Belgium, and the Western Half of Germany and some of Austria.