Tuesday, June 6, 2023, is the 79th anniversary of D-Day, when troops from the United States, United Kingdom and Canada landed on the beaches of France. The day was momentous because Allied soldiers infiltrated occupied Western Europe, entering through the beaches of Normandy, which were held by Nazi Germany. 

Timeline of D-Day

The Allied Forces, which fought against Nazi Germany and the Axis Powers during World War II, began to practice for D-Day in April 1944. They called their rehearsal Exercise Tiger, according to Military History Matters, an organization that shares historic information about wars. 

D-Day was supposed to be executed on June 5 but due to the weather, Gen. Dwight D. Eisenhower decided to switch to June 6, according to the U.S. Department of Defense.  

They planned to land in Normandy and spread about 160,000 soldiers across five beaches, to which they gave code names: Sword, Juno, Gold, Omaha and Utah. The operation was broken into a naval phase called "Neptune," which had troops traveling across the Channel to France, and "Overlord," which was the plan for the invasion and Battle of Normandy, according to The National World War II Museum.

Air efforts began early in the morning on June 6, 1944 – but American troops landed at 6:30 a.m. on Omaha Beach and soon Utah Beach, according to the D-Day Story, a museum in Portsmouth, U.K, just across the Channel from Normandy where some troops departed from. 

Shortly after – at 7:25 a.m. – British forces landed at Sword Beach and Gold Beach, with Canadian troops landing moments later at Juno Beach. 

The occupation of these beaches started the Battle of Normandy, during which Allied Forces pressed into German-occupied cities. On June 7, the British seized Caen, about 17 miles from the beach. U.S. forces pushed to Cherbourg on June 27. 

For about 12 weeks the Allied Forces battled the Germans across France and on Aug. 21, the Germans found themselves surrounded near the town of Falaise. This became known as the Falaise Pocket. On Aug. 25, U.S. and French troops liberated Paris. 

How many soldiers died on D-Day?

The Necrology Project, which continues to research and count those killed on D-Day, says 4,415 Allied soldiers were killed on June 6. About 2,500 of those killed were Americans and 1,913 were other Allied soldiers. The names of the fallen soldiers are marked on the Memorial Wall at the National D-Day Memorial in Virginia. 

Out of the 160,000 Allied soldiers that landed in Normandy, 9,000 were killed or injured within 24 hours, according to the U.S. Department of Defense. 

The U.S. invasions of Omaha and Utah were the bloodiest, because Germany's offenses were strong in these areas, according to the department. The sea was also rough and only two of 29 amphibious tanks even made it to shore. Many soldiers who stormed the beach were gunned down.

What does the D in D-Day stand for?

While D-Day and the Battle of Normandy were gripping, the reason it is called D-Day is anticlimactic. D simply stands for "day."

On June 12, 1944, a few days after the epic D-Day, Time Magazine explained the U.S. Army first started using the term in 1918 during World War I, writing in a field order: "The First Army will attack at H-Hour on D-Day with the object of forcing the evacuation of the St. Mihiel salient."

The military uses the terms H-Hour and D-Day to plan. D-Day marks an important event, and plus and minus signs are used to describe days around the event. For example, D+4 meant four days after; D-7 meant seven days before. Other big events during WWII also had their own "D-Days."

The French, however, say the D stands for disembarkation – the process of exiting a ship or vehicle. 

Eisenhower's executive assistant, Brig. Gen. Robert Schulz, said the "departed date" of an amphibious operation is abbreviated as D-Day, according to the Department of Defense. Therefore, D-Day would be used for the first day of this operation, and others during the war.

In:
• World War II

Caitlin O'Kane

Caitlin O'Kane is a digital content producer covering trending stories for CBS News and its good news brand, The Uplift.