D-Day is the biggest amphibious assault ever mounted, a vast operation which was years in the planning and was crucial to the outcome of the Second World War.
Here is a timeline of how the Longest Day unfolded:
5 June, 1944
22.00 - Operation Neptune, a seaborne force of five Allied assault groups consisting of 130,000 men, leaves the English coast in 6,939 vessels, travelling through channels already cleared by minesweepers.
6 June, 1944 - D-Day
00.05 - German coastal batteries between Le Havre and Cherbourg are bombed by the Allies.
00.20 - British airborne troops secure Pegasus and other bridges over the River Orne.
02.30-03.00 - Combined bombardment and assault fleets arrive and anchor.
04.30 - St Mere Eglise is captured by US airborne troops and roads leading up to Utah Beach are closed.
05.00 - Britain's 9th Battalion, the Parachute Regiment, helps destroy weapons at the Merville Battery thus protecting troops who will land at Sword Beach.
D-Day landings 70th anniversary: 20 facts about 'Operation Overlord'
D-Day landings 70th anniversary: 20 facts about 'Operation Overlord'
1/20 Troops from the 48th Royal Marines at Saint-Aubin-sur-mer on Juno Beach, Normandy, France, during the D-Day landings, 1944
Many soldiers landing on the beaches were wearing pyjamas under their battle dress. Lieutenant Herbert Jalland, of the Durham Light Infantry, said he and his battalion at Gold Beach wore them to stop backpacks chafing.
2/20 American craft of all styles pictured at Omaha Beach, Normandy, during the first stages of the Allied invasion in 1944
Writer J.D. Salinger was one of thousands of US soldiers landing at Omaha Beach. As well as provisions and weapons, he was carrying six chapters of his unfinished novel Catcher in the Rye in his backpack.
3/20 Royal Marine Commandos moving off the Normandy Beaches during the advance inland from "Sword" beach. The five beaches were known by their codenames, Sword, Gold, Juno, Omaha and Utah.
2,700 soldiers from the UK were either killed, wounded, went missing or were captured during the D-Day landings. Meanwhile, in the Houses of Commons, MPs debated changing the term "charladies" to "cleaners".
4/20 Royal Marine Commandos moving off the Normandy Beaches during the advance inland from "Sword" beach on 6 June 1944
During the drop at the first liberated village, Sainte-Mere-Eglise, American paratrooper John Steele's parachute got caught on the church spire. For two hours, Steele hung there playing dead before being taken prisoner by the Germans. Today, a dummy paratrooper hangs from the spire in his honour.
5/20 U.S. troops disembark from landing crafts during D-Day 06 June 1944 after Allied forces stormed the Normandy beaches.
Lieutenant James Doohan of the Winnipeg Rifles was saved by his silver cigarette case when he was shot in the chest on D-Day. It did not stop the shot to his hand that caused him to lose a finger. Doohan went on to playScotty in Star Trek. While on camera, he always tried to hide his injured hand.
6/20 Aerial view taken 6 June 1944 of the Allied Naval forces engaged in the Overlord operation of landing while Allied forces storm the Normandy beaches on D-Day
While the term “D-Day” is most closely linked to the Normandy landings, it in fact means the day on which a military operation begins – allowing the date for an operation to change without military planners having to change all the dates in their plan. The day before D-Day was D-1 and the day after was D+1.
7/20 British troops on their way to Normandy to take part in the D-Day landings
D-Day was originally planned for June 5 1944, but it was delayed by stormy weather. Thanks to intelligence operations to misdirect the Germans, even Hitler believed the "real" invasion was to come at Pas-de-Calais down the coast and the Normandy landings were merely a cover.
8/20 American troops stand by with stores on Omaha Beach after the D-day landings
Scottish meteorologist Group Captain James Stagg was appointed chief meteorological adviser to Eisenhower and persuaded him to delay the launch to allow for better weather. This decision saved the lives of thousands of soldiers although rough seas still hampered landings and the RAF struggled to bomb German fortifications through cloud cover.
9/20 British soldiers joke as they read a tourist guide about France aboard a landing craft while Allied forces storm the Normandy beaches on D-Day
As Allied troops pushed inland, the BBC broadcasts a message from Gen Eisenhower to the people of Normandy: 'The lives of many of you depend on the speed with which you obey. Leave your towns at once – stay off the roads – go on foot and take nothing with you that is difficult to carry. Do not gather in groups which may be mistaken for enemy troops.'
10/20 U.S. Army paratroopers of the 101st Airborne Division drive a captured German Kubelwagen on D-Day at the junction of Rue Holgate and RN13 in Carentan, France, 1944
In order to maintain the secrecy of the plan and build-up to D-Day, strategists used a series of code names and acronyms. "D-Day" meant the date of the operation, while "H-Hour" was the time. "Bolero" signified the build-up in Britain. "Operation Overlord" was the the name for the overall invasion plan, and "Operation Neptune" was the name of the seaborne invasion. "Ham and Jam" were the signals indicating the bridges at Benouville and Ranville were secured by Allied forces.
11/20 The body of a German soldier lies in the main square of Place Du Marche after the town was taken by U.S. troops who landed at nearby Omaha Beach in Trevieres, France, 1944
The first news report of the D-Day landings came from Gustav, an RAF homing pigeon released by the Reuters news agency correspondent Montague Taylor. Four pigeons, including Gustav, and one dog - an Alsatian called Brian - received the PDSA Dickin Medal for their life-saving actions.
12/20 U.S. Army troops make a battle plan in a farmyard amid cattle, which were killed by artillery bursts, near the D-Day landing zone of Utah Beach in Les Dunes de Varreville, France, 1944
Andree Auvray, now 88, was a fearful and heavily pregnant 18-year-old before the D-day landings. In an attempt to escape being killed by a bomb, she and her new husband slept in a ditch at her farm while keeping a small suitcase of baby clothes in case she gave birth in the trench. She gave birth 13 days later, in her dining room and her farm was transformed into a makeshift hospital for wounded civilians.
13/20 British Prime Minister Winston Churchill (L) walking with General Bernard Law Montgomery near the Rhine river in Germany during an advance by Allied troops on 23 March 1945.
Winston Churchill did not tell Parliament of the events in Normandy until midday on 6 June 1944. 'What a plan!' he said. 'This vast operation is undoubtedly the most complicated and difficult that has ever taken place.'
14/20 German Marshal Erwin Rommel (R) inspecting the 'Atlantic wall' in France, built to repel the landing of British and American forces during World War II.
On the morning of D-Day, Rommel was blissfully unaware of the invasion and was absent from his HQ at La Roche-Guyon, near Paris. He had returned home to Herrlingen in south-west Germany to celebrate his wife Lucie’s 50th birthday. He was later linked to a conspiracy to assassinate Hitler and forced to commit suicide.
15/20 Admiral Carleton F. Bryant (L) and USS Texas Commander Charles Baker being given the shell that struck the battleship.
During the Battle of Cherbourg, the shell crashed through the port bow directly below the and entered the stateroom of Warrant Officer M.A. Clark, but failed to explode. It was later disarmed and brought aboard as a lucky charm.
16/20 An couple watch a Canadian soldier with a bulldozer working in the ruins of a house in the rue de Bayeux on 10 July 1944. The church towers in the background have survived the Allied bombing intact in Caen, France
The devastating raids on Caen and other towns and villages in Normandy are still problematic for the French. Some feel the suffering of civilians has not been properly taken into account. Around 3,000 died on D-Day.
17/20 A large number of German prisoners on Juno Beach of Bernieres sur Mer guarded by British soldiers from the 2nd Army.
Richard Dimbleby, the father of BBC journalists David and Jonathan, led the team of BBC war correspondents who reported on D-Day and the liberation of north-west Europe. He was the corporation's first war reporter and the first correspondent to enter Bergen-Belsen concentration camp.
18/20 German prisoners are gathered and an American flag is deployed for signalling on Omaha Beach.
One of the flagship vessels of the naval operation was HMS Belfast. The vibrations of the ship’s gunfire during D-Day were so powerful that they cracked the crew’s toilets. She is now one of only three remaining vessels from the bombardment fleet.
19/20 A French armoured column passing through the small French town of St Mere Eglise on D-Day, gets a warm welcome from the inhabitants, 1944
The exact timings of the landings were decided using tide-prediction machines. By 1944, British mathematician Arthur Thomas Doodson had identified the exact time the landings should take place (H-Hour) and that D-Day should fall between 5 and 7 June.
20/20 A group of American soldiers stand at the village fountain in Sainte-Marie-du-Mont on 12 June 1944.
News of D-Day raised hopes for a swift end to the Second World War. When word reached POW camp Colditz, via an illegal radio hidden in an attic, prisoner Cenek Chaloupka vowed that if the war wasn’t over by December he’d run round the courtyard naked. On Christmas Eve 1944, Chaloupka ran round it in sub-zero temperatures. Twice.
06.00 - Bombers pound the German shore defences. More than 5,300 tonnes of bombs are dropped.
06.30 - American troops begin landing on Omaha Beach and face a devastating enemy onslaught which pins them there until 1100.
06.30 - American forces begin landing on Utah Beach.
07.10 - US 2nd Army Ranger Battalion attacks the Pointe du Hoc and defends it for the rest of the day.
07.25 - British troops land at Gold and Sword Beaches.
07.35 - Canadian regiments land at Juno Beach.
09.00 - General Eisenhower authorises release of communique announcing the invasion has begun and General Bradley calls for reinforcements.
09.45 - Enemy forces cleared from Utah Beach.
12.00 - Winston Churchill speaks to the House of Commons about the landings.
13.30 - Troops on Omaha Beach begin securing the area.
14.30 - The 21st Panzer Division unleashes a counter attack towards the coast.
16.00 - The British arrive at the coastal town of Arromanches.
18.00 - Some of the 3rd Canadian Division, North Nova Scotia Highlanders, reach three miles inland. 1st Hussar tanks cross the Caen-Bayeux railway, nine miles inland.
19.00 - Command post set up on Omaha Beach.
20.00 - Allied patrols at the outskirts of Bayeux.
7 June, 1944
00.00 - All the beaches are secure. By the end of day the Allies had disembarked more than 135,000 men and had bridgeheads of varying depths along the Normandy coastline.
But on Omaha the situation was perilous as the Germans fought for every inch of territory. By sunset a total of 10,000 men had been killed, injured or were missing.