This month marked the 75th anniversary of Operation Overlord, the Allied invasion of Normandy – a military campaign that marked more than anything else in public memory the expected defeat of Nazi Germany in World War II. True, there were more decisive battles – and it is enough to mention Stalingrad and Operation Bagration on the eastern front – but it is doubtful whether there were any battles that had such a dramatic touch. The campaign has produced hundreds of history books and many films, but it has not yet been researched and told in full.For some reason, the campaign is remembered as a one-day battle. This is reflected in the title of the famous book The Longest Day (Simon & Schuster, 1959) by historian and military correspondent Cornelius Ryan, as well as its film adaptation. But this is not the case. The campaign in northwest France was brutal and lasted for about three months, from D-Day until the liberation of Paris. Although Soviet propaganda scoffed at its Western allies and the war they fought, the campaign was certainly comparable with the eastern front. On D-Day itself, one day of extremely difficult fighting, there is no accurate data. The Germans suffered losses – dead and wounded – ranging from 4,000 to 9,000, while the Allies suffered about 4,500 dead and 6,000 wounded. True, many more were killed in the days of World War I, but even so, these are numbers that the mind does not grasp.Ryan’s book takes its name from the assertion by German Field Marshal Irwin Rommel that the first 24 hours of the invasion “will be decisive... for the Allies, as well as Germany, it will be the longest day.” The teams from the British and US armies who planned the invasion in 1942 concluded that it needed more troops, more ships, more planes and more armaments than any other single military operation in history. The preparations took about two years and required the total enlistment of millions of people.In June 1944, the most difficult decision was not whether to invade France, but when. The weather was less than optimal, and under such conditions, it was not at all clear whether it was worth invading. The heavy burden rested on the shoulders of one man: the commander of the Allied forces, General Dwight D. Eisenhower, who finally decided: “I am quite positive we must give the order... I don’t like it, but there it is.”On the other side was the German army, which could be described as the best army in the history of war. These soldiers, even in numerical inferiority and under harsh conditions, caused heavy losses to the armies that fought against them in a ratio of one-to-three. The fact that an amphibious landing operation is considered the most complicated military operation there is, served the Germans as well.DESPITE ALL the advanced technology, sophisticated fraud and inspiring leadership, the young and inexperienced soldiers determined – in their personal initiatives and immediate decisions – the fate of this complex operation. On the night between June 5 and June 6, 18,000 paratroopers dropped behind enemy lines in Normandy in order to isolate the area of operation from German reinforcements. Some actions became famous, such as Operation Deadstick – the capture of two bridges by a Glider infantry company (equivalent to modern day infantry assault by helicopters) from the British 6th Airborne Division, under the command of Major John Howard. His company landed in three gliders near the bridges and then “everybody stormed the bridge. There was bedlam. The Germans were shocked and disorganized. Grenades came into their dugouts and communications trenches.” The company completed its mission, seized the bridges intact and prevented the arrival of German armored forces to the coast.Another is the attack that destroyed a battery of German 105mm howitzers at Brécourt Manor, firing onto the principal exits from Utah Beach. Fifteen paratroopers of Easy Company from the 2nd Battalion, 506th Parachute Infantry Regiment (101st Airborne Division), led by Lieutenant Richard Winters, took down a superior German force and destroyed their guns. This was later described in the book Band of Brothers and its TV adaptation.The heaviest fighting was that of the forces that landed from the sea – and no force was required for a more difficult challenge than the American forces at Omaha Beach. “They came ashore on Omaha beach, the slogging, unglamorous men the no one envied,” Ryan wrote. “No battle ensigns flew for them, no horns or bugles sounded. But they had history on their side. They came from regiments that had bivouacked at places like Valley Forge, Stoney Creek, Antietam, Gettysburg, that had fought in the Argonne. They had crossed the beaches of North Africa, Sicily and Salerno. Now they had one more beach to cross.” The historian would note that the beach was later called the “bloody Omaha.”The most difficult task in Omaha – the conquest of the outposts in the cliffs of Pointe du Hoc – was assigned to the 2nd Ranger Battalion. “Small-arms fire [came] on Lieutenant Colonel James A. Rader’s three Ranger companies as they began the assault to silence the massive coastal batteries which intelligence said menaced the American beaches on either side.” The Rangers climbed on the cliffs and, under intense fire, they occupied the German positions. At the end of the day, only about 90 Rangers remained eligible for combat.When the landing forces looked back at the end of the day, their eyes saw the spectacular view of the active beachhead, bought at a heavy price. The fighting was not over. Only in France would it last for another three months – during which the Allied forces lost their momentum, and General George Patton’s combat leadership was required to lead Operation Cobra to defeat the German army. Still, the successful landing at Normandy opened the western front against Germany, turning Germany’s defeat into a matter of time.Seventy-five years after the battle that marked the end of Hitler, the battlefield on land – with all the capabilities and technological systems – has changed. However, there is still something to be learned from that battle in terms of planning, logistics, fraud and leading forces in battle. It is likely that Israel’s next confrontation – unlike the invasion of Normandy – will erupt in a time and place that the enemy will choose, whether it is Hamas or Hezbollah. But then, the IDF will have to surprise, dare and decide. Such a campaign will not last only one long day, but it is likely to begin with one – provided that it includes a determined operation of forces, in the air, on land and at sea. The writer is coordinator of the Military & Strategic Affairs and Cyber Security programs at The Institute for National Security Studies (INSS). He is also the founder and operator of the blog “In the crosshairs” on the military, security vision, strategy and practice.