A "humbled" US President Barack Obama led an emotional tribute on Friday to the thousands of troops who gave their lives to liberate Europe from Nazism, on the 70th anniversary of the D-Day landings that "shaped the security and well-being of all posterity."
Speaking at Omaha Beach in front of veterans resplendent in military uniforms complete with medals glittering in the sun, Obama said that their sacrifice and bravery had breached "Hitler's Wall" and secured today's era of democracy and freedom.
"By the end of that longest day, this beach had been fought, lost, refought and won -- a piece of Europe once again liberated and free. Hitler's Wall was breached, letting loose Patton's Army to pour into France," said a visibly moved Obama in a speech interrupted by a lengthy standing ovation.
"Gentlemen, we are truly humbled by your presence today," he told the veterans, many of whom were confined to wheelchairs and, well into their 80s, were likely marking the anniversary of that historic day for the last time.
"Omaha -- Normandy -- this was democracy's beachhead. And our victory in that war decided not just a century, but shaped the security and well-being of all posterity."
After his speech, Obama warmly embraced a stooped veteran almost half his size before bowing his head alongside French President Francois Hollande at a wreath commemorating the thousands that fell on June 6, 1944.
The two leaders then stood, hands on heart, with saluting veterans standing to attention behind them as a lone bugler sounded out and jets roared a fly-past through a gloriously blue sky.
For his part, Hollande said France would "never forget what it owes the United State."
"This day, which began in chaos and fire, would end in blood and tears, tears and pain, tears and joy at the end of 24 hours that changed the world and forever marked Normandy," he said as he opened the ceremonies.
Britain's Queen Elizabeth II, dressed in a lime green coat and matching hat, led a service at Bayeux cemetery where nearly 5,000 Commonwealth troops are buried.
- 'Diplomatic deep-freeze' -
Some 20 heads of states, royals and prime ministers were to mingle with veterans throughout the day at ceremonies on the beaches of northern France, where the biggest amphibious assault in history was launched in 1944.
Dignitaries -- including the queen, who at the age of 88 is making a now rare foreign trip, and sparring world leaders Obama and Russian President Vladimir Putin -- will have lunch together at a grand chateau before heading to the beaches for a solemn international ceremony.
The D-Day ceremonies will give world leaders feuding over the Ukraine crisis a rare common purpose but the diplomatic wrangling over the worst East-West confrontation since the Cold War started in earnest on Thursday and continued throughout the anniversary.
Putin has been in the diplomatic deep-freeze since Russia's annexation of Crimea in March and held his first meeting with Western leaders since then -- a bilateral with Britain's David Cameron and a late-night meal with French President Francois Hollande.
Paris was the centre of a frenzied bout of gastro-diplomacy late on Thursday, as Hollande gobbled down a rushed dinner with Obama before hosting the Russian leader for 'supper' at the Elysee Palace.
Putin and German Chancellor Angela Merkel continued the shuttle diplomacy Friday in northern France as French Foreign Minister Laurent Fabius said Hollande had told the Kremlin strongman Ukraine was descending into "virtually all-out war" and stressed the urgent need for a truce.
Obama was not scheduled to meet Putin officially but told reporters after a meeting of the group of seven rich countries in Brussels that he had "no doubt that I'll see Mr Putin."
For his part, Putin has stressed that he does not wish to avoid anyone and may hold talks with Ukraine's president-elect Petro Poroshenko.
- 'A hairy time' -
Away from the diplomatic dance, veterans marked the occasion with low-key humility.
One British veteran, 89-year-old Ken Godfrey, was applauded by well-wishers who shouted "bravo" and "thank you" as, medals clinking on his chest, he walked the mile-long path to Bayeux cemetery.
"My main memory is wading through the sea with water up to my chest," he told AFP. "But I don't like to talk about the fighting. If people ask, I just say we had a hairy time. But I'm lucky that I survived."
Bob Cowper, a 91-year-old wheelchair-bound Australian night fighter pilot, met his current prime minister Tony Abbott at the Bayeux ceremonies and told AFP that he flew over the beaches on D-Day as the fighting raged below.
"Looking down, even though we were making a contribution, I remember feeling empathy for all the poor buggers fighting on the ground."
It was Cowper's first trip back to the beaches where he saw so many comrades cut down but he beamed with pride at being present at the ceremonies.
"It's wonderful as an old man of 91 - it's like coming home."