President Barack Obama on Saturday promised the United States would never forget the dead of D-Day in 1944, saying the Allied troops killed on Normandy's beaches changed history.
Obama eulogized more than 9,387 US soldiers killed during the Battle of Normandy, buried at a cemetery overlooking Omaha beach, where US forces stormed ashore under torrents of Nazi fire, 65 years ago to the day.
"Friends and veterans, we cannot forget -- what we must not forget -- is that D-Day was a time and a place where the bravery and selflessness of a few was able to change the course of an entire century," Obama said.
"At an hour of maximum danger, amid the bleakest of circumstances, men who thought themselves ordinary found within themselves the ability to do something extraordinary," Obama said, apparently implying modern day Americans should also unite in a time of crisis to defy the challenges of their age.
The president also sought lessons of from a time when Allied nations stood together to defeat tyranny.
"The nations and leaders that joined together to defeat Hitler's Reich were not perfect.
"We had made our share of mistakes, and had not always agreed with one another on every issue. But whatever God we prayed to, whatever our differences, we knew that the evil we faced had to be stopped."
As Obama spoke, he looked over rows of white headstones in the shape of crosses in the distance, each marked by miniature US and French flags, honoring members of the so-called "Greatest Generation" who perished.
The president, at a ceremony also attended by French President Nicolas Sarkozy, Canadian Prime Minister Stephen Harper and Britain's Prime Minister Gordon Brown and Prince Charles, also paid tribute to around 200 ageing veterans who traveled to France.
"You remind us that in the end, human destiny is not determined by forces beyond our control," Obama said.
"You remind us that our future is not shaped by mere chance or circumstance," a few hundred yards (metres) from where more than 3,600 US servicemen died in the carnage of June 6, 1944.
"Our history has always been the sum total of the choices made and the actions taken by each individual man or woman. It has always been up to us."
Obama remembered one veteran, the final pilgrimage to fallen comrades made by Jim Norene of the 101st Airborne Division.
"Last night, after visiting this cemetery for one last time, he passed away in his sleep," Obama said.
"Jim was gravely ill when he left his home, and he knew that he might not return. But just as he did sixty-five years ago, he came anyway. May he now rest in peace with the boys he once bled with."
Obama spoke on the penultimate day of a four-nation tour of Europe and the Middle East, which included a landmark speech in Cairo at which he vowed to forge a "new beginning" between America and the Muslim world.
Earlier, before honoring the dead of wars past, Obama turned to preventing future conflicts after talks with Sarkozy in the Normandy city of Caen.
He said North Korea's nuclear weapons test had been "extraordinarily provocative" and it would be "profoundly dangerous" for Iran to get a nuclear bomb.
Days after visits to Saudi Arabia and Egypt designed to revive the stalled Middle East peace process, Obama also said it was vital for all sides in the region to recognise their fate was inextricably linked.
Earlier, veteran H Smith Shumway, 87, a US lieutenant who came ashore on D-Day, walked between graves of dead comrades, remembering how he had jumped off a landing craft into knee-deep water and fought his way up the beach.
Shumway, originally from Utah, who now lives in Washington DC, who was blinded by an anti-tank mine in July 1944.
Shumway has been trying to find the remains of a US spy, who was captured and killed after they lost contact on a night patrol soon after D-Day.
Last year, the US military mounted a dig in a field near Colleville-Sur-Mer, without success. Shumway and his family now plan to hire to a ground penetrating radar to find the remains.
"I hope we find him this time," he said.
Among guests at the ceremony was Tom Hanks, star of "Saving Private Ryan" which begins with graphic scenes of the Normandy landings.
Former Republican presidential candiate, senator and wounded World War II hero Bob Dole was also at the event as was Charlie Payne, Obama's great uncle, who took part in the liberation of the Buchenwald Nazi concentration camp in Germany which Obama visited on Friday.