A quick look: D-Day, the largest amphibious invasion in history

• D-Day was the Allied troops invasion in Normandy, France, on June 6, 1944, having been delayed by 24 hours because of poor weather, to fight Nazi Germany in World War II. It was the largest amphibious invasion in history.
• The planners were particular about the timing of D-day. They wanted a full moon, with a spring tide. They wanted to land at dawn on a flood tide, when it was about halfway in. That meant there were only a few days that were appropriate. June 5th was chosen but it had to be delayed 24 hours for bad weather.

• The forecast was so bad that the German commander in Normandy, Erwin Rommel, went home to give his wife a pair of shoes on her birthday. He was in Germany when the news came.
• The “D” stands for Day. D-Day is code for the day an important military attack is scheduled to begin.
• The code name for the invasion was Operation Overlord.
• Code names for the five beaches where the Allies landed: Utah, Omaha, Gold, Juno, and Sword.

• In 1944, by a huge coincidence, a crossword puzzle was printed with answers all containing D-Day operation “code names”, which sent MI-5 into a panic thinking their invasion plans had been discovered.
• To plan for the operation the BBC ran a competition for French beach holiday photographs. It was a way of gathering intelligence on suitable beaches.
• The British were to land at Gold Beach, east of Omaha; then the Canadians at Juno; and the British again at Sword, the easternmost invasion beach. Allied airborne troops would be dropped by parachute or glider and secure the flanks ­– the Americans in the west and the British and Canadians in the east.

• The term ‘H-Hour’ was also used – the time of the landings – which was 6.30am on the two western beaches (Utah and Omaha); an hour later at 7.30am a little further to the east for the British landings; and 7.45am for the Canadians at Juno.

• Roughly 160,000 Allied troops crossed the English Channel, supported by seven thousand ships and boats, and landed on the coast of Normandy. The seaborne invasion included nearly 5,000 landing and assault craft, 289 escort vessels, and 277 minesweepers. More than 13,000 aircraft.

British British WW2 veteran, Lewis Trinder, 94, poses for pictures with history enthusiasts near the Normandy coast ahead of the 75th D-Day anniversary, in Arromanches, France. EPA-EFE/IAN LANGSDON

• For the D-Day invasion all Allied aircraft had black and white stripes painted on the underside of their wings for easy identification. Likewise, all military vehicles had a white star in a white circle painted on them, regardless of nationality.
• Not all D-Day objectives were achieved, but the airborne troops did secure the flanks as planned and landings were broadly very successful.

Parachutists in WW2 attire drop in a field near the Normandy coast ahead of the 75th D-Day anniversary, in Carentan, France. EPA-EFE/IAN LANGSDON

• The French Resistance begin to sabotage the German response to the Normandy invasion on D-Day, by blowing up telephone exchanges and railway lines.
• On the night of the D-Day invasion, only 15% of paratroopers landed in the right place. The Allies parachuted dummies over Normandy on D-day to distract Nazi gunners from the real paratroopers.

• The SAS masterminded parachute drops in which hundreds of dummies were thrown out of aircraft to confuse the Germans as to where the landings were going to be.
• Allied soldiers’ home nations: United States, Britain, Canada, Belgium, Norway, Poland, Luxembourg, Greece, Czechoslovakia, New Zealand and Australia (+177 French commandos).
• The British infantryman was paid £3 15s a month, the Americans got £12.
• All D-Day troops were given ‘clickers’ as a means of identification in the dark, regardless of language. A click indicated a ‘friendly’ response – no such response indicated the enemy.
• When the D-Day forces landed, Hitler was asleep. None of his generals dared send re-enforcements without his permission, and no-one dared wake him.

• The first allied soldier killed was Lieutenant Herbert Denham ‘Den’ Brotheridge, just after midnight on the 6th, while leading a charge to seize Pegasus Bridge.
• The casualties: The traditional allied death toll for the whole of D-day is given as 2,500. However recent research suggests that it might be around twice that figure. German casualty figures on D-Day are not at all precise, but estimates put them at a similar number. Some 15,000 French civilians were killed.

• 4% of the sand on Normandy beaches are still made up of metal particles from D-Day landings.
• In 1942, the Canadians and the British Navy launched a practice invasion of France, the “Dieppe Raid.” 20% were killed, 10% wounded, 30% captured. The lessons learned in that disaster lead to D-Day’s success.

• The planners of Operation Overlord and D-Day needed to convince the Germans that Pas-de-Calais, the area of France closest to Britain, was the target for the Allied invasion of occupied France. Operation Fortitude was the code name given to the Allied military deception plan to fool the Germans into believing that the invasion of Europe on D-Day would occur at Pas-de-Calais, rather than in Normandy. The Operation Fortitude deception campaign included placing decoys such as inflated rubber tanks, dummy aircrafts, dummy landing craft, dummy parachutists and empty tents along the British coast opposite Calais. The decoys all looked genuine to the German spy planes who flew over the area and helped to mislead the enemy on the Allies true intention for D-Day.
• Movies about D-Day: Red Ball Express (1952) The Longest Day (1962), The Americanization of Emily (1964), Overlord (1975) The Big Red One (1980), Saving Private Ryan (1998), Band of Brothers (2001).