Warmatrix

The Normandy landings, commonly called D-Day, were the largest amphibious assault in history. They opened a third front over which nazi Germany was attacked, hastening its downfall in World War II.
After the Wehrmacht had defeated France and the Low Countries in 1940 CE, Britain was Germany's only opponent left in the west, though in the east the USSR was attacked a year later with Operation Barbarossa. In that same year the USA joined the war, though needed time to gear up a war economy. The USSR was very hard pressed and soon Josef Stalin strongly requested that the western allies opened a second front. He had to wait for three years before they were ready. In 1943 CE the Germans were chased out of north Africa and Italy was attacked; another year later the allies launched an invasion from the west.
The Germans had prepared for the attack by constructing a line of fortifications running all the way from southern France to northernmost Norway: the "Atlantikwall", the Atlantic Wall. It was not yet complete, though already a serious obstacle. They expected the assault at the Pas de Calais, where the Channel is the narrowest, and concentrated their strongest defenses there. The allies played at that conviction by leaking large amounts of misinformation, including a ghost army commanded by George Patton, which suggested that they would indeed attack there. In fact they had chosen Normandy as their landing site. The lack of good harbors, essential for bringing in supplies afterwards, was partially solved by bringing two artificial "Mulberry" harbors.
The invasion force was large: 160,000 combat troops and a more or less equal number of support troops. The first wave consisted of 3 divisions of airborne troops. On Day itself 5 divisions spearheaded the amphibious assault, one on each beach area: 'Sword', 'Juno', 'Gold', 'Omaha' and 'Utah'. The attackers were supported by nearly 5,000 landing craft, 275 minesweepers, 290 other ships and a huge air force, giving the allies near total sea and air superiority. The Germans had 20 divisions in Scandinavia, 66 divisions stationed in France and the Low Countries, some 15 of which in or close to Normandy. These were a mix of poorly equipped, poorly trained conscripts and far stronger veteran troops. They were hampered by allied bombing raids and sabotage by French resistance fighters.
The invasion relied on full moon, high tide and good weather. It was originally planned for 1 May, but problems with assembling landing craft delayed it until 5 June. Bad weather postponed it further, however general Dwight Eisenhower weighed his options and decided to go ahead on 6 June. This surprised the Germans, who considered the weather too bad for an attack. Many German commanders were away on weekend leave, trusting that the invasion would not come on the 6th.
In the night of 5 - 6 June airborne troops were dropped behind the Atlantikwall to secure bridges, road crossings and strongpoints. Some were very successful, like the British paratroopers who captured the bridge over the Orne; others landed scattered and ended up in flooded fields. Their fragmentation prevented several units from achieving their objectives, though the chaos confused the Germans too. At dawn the forward troops were joined by attacking bombers and a naval bombardment by battleships, cruisers and destroyers, both of which were hampered by low hanging clouds.
Following the big guns were minesweepers that cleared paths for the landing craft. Despite rough weather, some strong currents, many mines and German resistance, the landings at 4 of the 5 beaches went relatively smooth. There were troubles, like men arriving before their equipment and the heavy fight for the gun emplacement at Pointe du Hoc that proved to have been emptied, but almost everywhere the troops moved inland soon. The Americans fared worse at Omaha beach. There the naval guns had overshot the German bunkers and bombers had failed to hit them too, so many were intact when the Americans landed. German artillery and machine guns, firing from an escarpment, provided a hot and deadly welcome. 2,000 casualties were suffered and by nightfall the Americans had moved only 1 kilometer inland. Assistance by destroyers that sailed very close to the shore was essential in preventing a disaster.
A strong German counterattack could have been devastating to the overall operation. However because of conflicts among the German generals the command of the panzer reserves was divided. Continuous arguments, both before and during the invasion, kept half of them out of the action and the other half acting too slow to make a real impact. One panzergrenadier battalion managed to fight its way to the beach between Sword and Juno, but then pulled back in fear of being cut off. All in all the German response to the attack was slow, confused and half-hearted, partly from their own disorganization, partly from the efforts of the allies.
At the end of D-Day 155,000 allied troops had landed at the cost of 10,000 casualties against 4,000 - 9,000 German losses. The casualties were much lighter than the allied commanders had feared. From most beaches the attackers had moved about 8 - 10 kilometers inland; from Omaha only 2. This was far short of the objectives. The slow British advance from Sword had prevented the capture of Caen, which would not be liberated until weeks later. It took six more days of fighting before the five beachheads were finally linked up with each other. The rest of Operation Overlord took even longer because of rapidly stiffening German resistance and difficult 'bocage' terrain, full of hills, woods and hedges. The allies did not break out of the landing zone until early August, during Operation Cobra.
D-Day was partly won by superb planning and the bravery of the invading troops, but mostly by the overwhelming allied air superiority, which disrupted German communications, supply lines and forced German panzers to lie low. The Germans were helped most by the terrain, yet ultimately failed to contain the allies. Despite the success of the Normandy landings, the later outbreak and offensives, on D-Day only about 25% of German strength was assigned to the western front, rising to 33% in late 1944 CE. However for the post-war fate of western Europe, including Germany itself, D-Day was a vital first step.