13 Memorable Facts About D-Day

The Normandy landings—an event better known as D-Day—became a pivotal moment in World War II. Heavy losses were inflicted on both sides, but with planning, deception, and semiaquatic tanks, the Allied forces pulled off what is considered the biggest amphibious invasion in history. Here are a few things you should know about the historic crusade to liberate France from Nazi Germany.

1. D-Day occurred on June 6, 1944.
2. Normandy was chosen as the D-Day landing site because the Allies were hoping to surprise German forces.
3. D-Day action centered around five beaches with inscrutable code names.
4. Pulling off the D-Day landings involved elaborate trickery.
5. D-Day was planned with the help of meteorologists.
6. D-Day was a common military term with an uncertain meaning.
7. D-Day was among the largest amphibious assaults in military history.
8. The Allies also had floating tanks.
9. When the D-Day attack started, Adolf Hitler was asleep.
10. Eisenhower was fully prepared to accept blame if things went badly on D-Day.
11. Knocking out German communications was one of the keys to victory on D-Day.
12. Theodore Roosevelt’s son earned the Medal of Honor.
13. D-Day was the opening chapter in a long campaign.

D-Day occurred on June 6, 1944.

The D-Day invasion was several years in the making. In December 1941, the United States formally entered World War II. Shortly thereafter, British and American strategists began entertaining the possibility of a huge offensive across the English Channel and into Nazi-occupied France. But first, the Allies swept through northern Africa and southern Italy, weakening the Axis hold on the Mediterranean Sea. Their strategy resulted in Italy’s unconditional surrender in September 1943 (though that wasn’t the end of the war in Italy). Earlier that year, the Western Allies started making preparations for a campaign that would finally open up a new front in northwestern France. It was going to be an amphibious assault, with tens of thousands of men leaving England and then landing on France’s Atlantic coastline.

Normandy was chosen as the D-Day landing site because the Allies were hoping to surprise German forces.

Since the Germans would presumably expect an attack on the Pas de Calais—the closest point to the UK—the Allies decided to hit the beaches of Normandy instead. Normandy was also within flying distance of war planes stationed in England, and it had a conveniently located port.

D-Day action centered around five beaches with inscrutable code names.

Altogether, the D-Day landing beaches encompassed 50 miles of coastline [PDF]. The Canadian 3rd Division landed on the section code-named “Juno,” British forces touched down on “Gold” and “Sword,” and Americans were sent to “Utah” and “Omaha.” Of the five beaches, Omaha had the most bloodshed: Roughly 2400 American casualties, plus 1200 German casualties, occurred there. How the beaches got their code names is a mystery, although it’s been claimed that American general Omar Bradley named Omaha and Utah after two of his staff carpenters, who hailed from Omaha, Nebraska, and Provo, Utah.

Pulling off the D-Day landings involved elaborate trickery.

If the Allies landed in France, Adolf Hitler was confident that his forces could repel them. “They will get the thrashing of their lives,” he boasted. But to do that, the German military would need to know exactly where the Allied troops planned to begin their invasion—so the Allies kicked off a misinformation campaign in 1943.

Using everything from phony radio transmissions to inflatable tanks, they successfully convinced the Germans that the British and American forces planned to make landfall at the Pas de Calais. The Germans kept a large percentage of their troops stationed there (and in Norway, the rumored target of another bogus attack). That left Normandy relatively under-defended when D-Day began.

D-Day was planned with the help of meteorologists.

The landings at Normandy and subsequent invasion of France were code-named “Operation Overlord,” and General Dwight D. Eisenhower, the the Allies’ top commander, led the operation. To choose the right date for his invasion, Eisenhower consulted with three different teams of meteorologists, who predicted that the weather would be best on June 5, 6, or 7; if not then, they'd have to wait for late June.

Originally, Eisenhower wanted to start the operation on June 5, but the weather didn’t cooperate. “There were very high winds, and Eisenhower made the decision to wait 24 hours. However, 24 hours later, the Americans predicted there would be a break in the storm and that conditions would be difficult, but not impossible,” said oceanographer Walter Munk, who developed the research that allowed the Allies to predict ideal conditions. Ultimately, Eisenhower began the attack on June 6, even though the weather was less than ideal. It’s worth noting that if he’d waited for a clearer day, the Germans might have been better prepared for his advance. (Fortunately, the Allies didn’t wait until late June: There was a massive storm on their proposed dates.)

D-Day was a common military term with an uncertain meaning.

A few years after Eisenhower retired from public life, he was asked if the D in D-Day stood for anything. His aide, Brigadier General Robert Schultz, said that “any amphibious operation has a ‘departed date’; therefore the shortened term D-Day is used.” [PDF]. Other sources suggested the D stood for disembarkation, day (as a code word), and day of decision.

D-Day was among the largest amphibious assaults in military history.

On D-Day, more than 156,000 Allied troops—representing the United States, the United Kingdom, Canada, Australia, Belgium, Czechoslovakia, France, Greece, New Zealand, Norway, and Poland—landed on the beaches of Normandy. They were accompanied by almost 7000 nautical vessels. In terms of aerial support, the Allies deployed more than 10,000 individual aircrafts, which outnumbered the German planes 30 to one.

The Allies also had floating tanks.

The Sherman Duplex Drive Tanks (a.k.a. “Donald Duck” tanks) came with foldable canvas screens that could be unfurled and turn the vehicle into a crude boat. Once afloat, the tanks were driven forward with a set of propellers. They had a top nautical speed of just under 5 mph. The Duplex Drives that were sent to Juno, Sword, and Gold beaches fared a lot better than those assigned to Omaha or Utah. The ones sent to Omaha mostly sank because they had to travel across larger stretches of water and encountered choppier waves.

When the D-Day attack started, Adolf Hitler was asleep.

On the eve of D-Day, Hitler was entertaining Joseph Goebbels and some other guests at his home in the Alps. The dictator didn’t go to bed until 3 a.m. Three-and-a-half hours later, at 6:30 a.m., the opening land invasions at Normandy began, with ground troops joining the Allied gliders and paratroopers that had been landing nearby since 12:16 a.m. Hitler was finally roused at noon when an aide informed him about the massive assault underway in Normandy. Hitler didn’t take it seriously and was slow to authorize a top general’s request for reinforcements. That mistake proved critical.

Eisenhower was fully prepared to accept blame if things went badly on D-Day.

As Hitler partied in the Alps, Eisenhower was drafting a bleak message. The success of Operation Overlord was by no means guaranteed, and if something went horribly awry, Eisenhower might have no choice but to order a full retreat. He preemptively wrote a brief statement that he intended to release if the invasion fell apart.

“Our landings in the Cherbourg-Havre area have failed to gain a satisfactory foothold and I have withdrawn the troops,” it said. “My decision to attack at this time and place was based upon the best information available. The troops, the air and the Navy did all that bravery and devotion to duty could do. If any blame or fault attaches to the attempt it is mine alone.”

Knocking out German communications was one of the keys to victory on D-Day.

Hitler may not have had all of his troops in the right spot, but the Germans who had been stationed at Normandy did enjoy some crucial advantages. At many localities, Omaha Beach included, the Nazi forces had high-powered machine guns and fortified positions. That combination enabled them to mow down huge numbers of Allied troops. But before dawn broke on June 6, British and American paratroopers had landed behind enemy lines and taken out vital lines of communication while capturing some important bridges. Ultimately, that helped turn the tide against Germany.

Theodore Roosevelt’s son earned the Medal of Honor.

The 56-year-old Brigadier General Theodore Roosevelt Jr. led the first wave of troops on Utah Beach. The men, who had been pushed off course by the turbulent waters, missed their original destination by over 2000 yards. “We’re going to start the war from right here,” Roosevelt told them. Despite having arthritis, Roosevelt insisted on putting himself right in the heart of the action and the beach was taken in short order. Roosevelt died of natural causes one month later and was posthumously awarded the Medal of Honor for “gallantry and intrepidity at the risk of his life above and beyond the call of duty on 6 June 1944.”

D-Day was the opening chapter in a long campaign.

The Normandy invasion was not a one-day affair; it raged on until Allied forces crossed the Seine in August 1944. Altogether, the Allies suffered about 200,000 casualties over the course of the campaign—including 4413 deaths on D-Day alone. While no reliable figures for the number of German casualties have been confirmed, historians estimate that 200,000 were killed or injured, and another 200,000 were taken prisoner. On May 7, 1945—less than a year after D-Day—Germany surrendered, ending the war in Europe.

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A version of this story ran in 2019; it has been updated for 2024.