June 1944 was a major turning point of World War II, particularly in Europe. Although the initiative had been seized from the Germans some months before, so far the western Allies had been unable to mass sufficient men and material to risk an attack in northern Europe.
By mid-1944 early mobilization of manpower and resources in America was beginning to pay off. Millions of American men had been trained, equipped, and welded into fighting and service units. American industrial production had reached its wartime peak late in 1943. While there were still critical shortages -- in landing craft, for instance -- production problems were largely solved, and the Battle of the Atlantic had been won. Ever increasing streams of supplies from the United States were reaching anti-Axis fighting forces throughout the world.
By the beginning of June 1944, the United States and Great Britain had accumulated in the British Isles the largest number of men and the greatest amount of materiel ever assembled to launch and sustain an amphibious attack. Strategic bombing of Germany was reaching its peak.
In May 1943, the Combined Chiefs of Staff had given high priority to a Combined Bomber Offensive to be waged by the Royal Air Force and the U.S. Army Air Forces. By late summer 1943, Allied bombers were conducting round-the-clock bombardment of German industry and communications. In general, British planes bombed by night and American planes bombed by day. Whereas an air raid by 200 planes had been considered large in June 1943, the average strike a year later was undertaken by 1,000 heavy bombers.
After considerable study strategists determined to make the cross-channel attack on the beaches of Normandy east of the Cherbourg Peninsula. Early objectives of the operation were the deep-water ports at Cherbourg and at Brest in Brittany.
Three months before D-Day, a strategic air campaign was inaugurated to pave the way for invasion by restricting the enemy's ability to shift reserves. French and Belgian railways were crippled, bridges demolished in northwestern France, and enemy airfields within a 130-mile radius of the landing beaches put under heavy attack. Special attention was given to isolating the part of northwestern France bounded roughly by the Seine and Loire Rivers. The Allies also put into effect a deception plan to lead the Germans to believe that landings would take place farther north along the Pas de Calais.
Opposed to the Allies was the so-called Army Group B of the German Army, consisting of the Seventh Army in Normandy and Brittany, the Fifteenth Army in the Pas de Calais and Flanders, and the LXXXVIII Corps in Holland -- all under command of Field Marshal Erwin Rommel. Commander of all German forces in western Europe was Field Marshal von Rundstedt who, in addition to Group B, also had at his disposal Group G composed of the First and Nineteenth Armies. In all, Von Rundstedt commanded approximately fifty infantry and ten Panzer divisions in France and the Low Countries.
Despite unfavorable weather forecasts, General Eisenhower made the decision to attack on June 6, 1944. At 0200 that morning one British and two American airborne divisions were dropped behind the beaches in order to secure routes of egress from the beaches for the seaborne forces. After an intensive air and naval bombardment, assault waves of troops began landing at 0630. More than 5,000 ships and 4,000 ship-to-shore craft were employed in the landings. British forces on the left flank and U.S. forces on the right had comparatively easy going, but U.S. forces in the center (Omaha Beach) met determined opposition. Nevertheless, by nightfall of the first day, large contingents of three British, one Canadian, and three American infantry divisions, plus three airborne divisions, had a firm foothold on Hitler's "fortress Europe."
[Note: The primary source for this text is the U.S. Army Center for Military History.]