AMNA NAWAZ: Eighty years ago tomorrow, the liberation of Europe from the horrors of the Nazis began with Operation Overlord, the Allied invasion of Normandy.

Nearly 200,000 soldiers, principally Americans, Brits and Canadians, landed on June 6 of 1944 across five beach sectors, Utah, Omaha, Gold, Juno, and Sword.

Malcolm Brabant is in Northern France and met some of the veterans of D-Day, now all around 100 years old, to begin our coverage of this 80th anniversary.

CHIEF MASTER SGT.

MEL JENNER (RET)., U.S. Army Air Corps: The bodies in the water, they looked like logs floating in the water.

MALCOLM BRABANT: Sergeant Mel Jenner had perhaps the best view of D-Day, flying in a top secret mission, photographing the invasion.

CHIEF MASTER SGT.

MEL JENNER (RET).

: I couldn't believe that all of all those young guys down in that water would give their life for their country and the world, to be exact.

MALCOLM BRABANT: East of Omaha, British beaches also have their ghosts.

BILL WRIGHT, British Army Veteran: One of the great things about the war was the comradeship.

You were really comrades with your mates.

MALCOLM BRABANT: Bill Wright on the far right, and his Sherman tank crew came ashore at Sword Beach near where a Norwegian destroyer was sunk on D-Day.

BILL WRIGHT: We'd known for some time, of course, what was going to happen, and we knew that we were making history.

And that was a terrific boost to morale, as you could imagine.

REAR ADM. JOHN ROBERTS (RET.

), Royal Navy Veteran: I was just 20 years old.

At that age, young man don't want to miss out on anything.

I was so pleased that I was there.

MALCOLM BRABANT: Sublieutenant John Roberts had already seen action escorting convoys across the North Atlantic.

On D-Day, his ship's big guns battered German defenses.

REAR ADM. JOHN ROBERTS (RET.

): The noise was quite fantastic.

There must have been 100 warships bombarding the coast.

NARRATOR: From the skies, hundreds of planes provided air cover for the seaborne invasion below.

JIM KUNKLE, U.S. Army Corps Veteran: I was flying P-38 Lightnings.

And we were given the mission to protect all the shipping from England to Normandy.

There were 5,000 boats out there, and we expected the Luftwaffe to really hit them.

What an opportunity.

And we didn't see one.

I mean, it was actually a boring sort of mission for us.

MALCOLM BRABANT: Jim Kunkle still possesses a certain all-American swagger that, sometimes during the war, aggravated the less flamboyant British.

How old are you, sir?

JIM KUNKLE: A hundred and one, shooting for 102 in October.

MALCOLM BRABANT: What does it mean to you to be back here?

JIM KUNKLE: Well, it's lots of memories.

You never forget.

MALCOLM BRABANT: Paratrooper Henry Langrehr was among the first into action, aged 19.

HENRY LANGREHR, U.S. 82nd Airborne Veteran: We took a shell off the corner of our wing, and shrapnel came through the plane and killed one man on one side of me and he on the other side.

So, there was a lot, a lot of flak, just like the Fourth of July.

MALCOLM BRABANT: And how glad were you to get out of the airplane?

HENRY LANGREHR: I wanted to get out right away.

Didn't want to be in that plane no more.

MALCOLM BRABANT: The 82nd Airborne's target, the Nazi-occupied town of Sainte Mere Eglise, where Private John Steele is immortalized.

After his chute snagged on the spire, Steele played dead for two hours until the Germans captured him.

HENRY LANGREHR: John was taken prisoner, and we took the city and we freed all of those guys.

MALCOLM BRABANT: Sainte Mere Eglise is a shrine for paratroopers like Sergeant Andrew Kadick.

SGT.

ANDREW KADICK, U.S. 171st Airborne: There's a reason why in the United States we call that generation the Greatest Generation.

The idea of jumping out of an aircraft with all of your equipment just to land under hostile fire, and then put your own weapon into action to fight the enemy, an experienced and seasoned enemy in a foreign land, is something truly remarkable.

MALCOLM BRABANT: But there's a warning from Claire Horton, who leads Britain's Commonwealth War Graves Commission, after a survey revealed that less than half of all young people know what happened on D-Day.

CLAIRE HORTON, Director General, Commonwealth War Graves Commission: It's a worry if we have young people who are just not understanding why things happened and the fact that we all live actually pretty free lives here.

There's a problem that history might repeat itself.

MALCOLM BRABANT: If anyone symbolizes the purpose of D-Day, it's 86-year-old Leon Malmed from California, now back in his native France, traveling with U.S. veterans.

LEON MALMED, France: I feel that I owe my life 100-plus percent to America.

MALCOLM BRABANT: Five-year-old Leon and his older sister Rachel (ph) lived in the town of Compiegne with mother Hannah (ph) and father Saul (ph), when, in 1942, their parents were taken away by the Nazis because they were Jews.

At great personal risk, neighbors Suzanne (ph) and Henri Ribouleau (ph) stepped into the breach.

LEON MALMED: So at that time, Henri Ribouleau said: "Do not worry, Mr. and Mrs. Malmed, we will take care of your children until you come back," not knowing that they would be gone forever.

So that was the -- that was the last time that we would see our parents.

MALCOLM BRABANT: Three months after landing in Normandy... NARRATOR: Our beachhead to Berlin was established.

MALCOLM BRABANT: ... American troops liberated Leon's hometown, ending three years of terror.

LEON MALMED: But the windows of the street were just covered with flags.

And people were absolutely -- it was the best day of my life, for sure.

MALCOLM BRABANT: This anniversary is tinged with mixed emotions, pride, respect, and that often misused word awe, that so many veterans have returned to the beaches that were part of what history acknowledges as the longest day.

But there's also sadness that, in all probability, this will be their last big hurrah.

CHIEF MASTER SGT.

MEL JENNER (RET).

: When anybody wants to talk about somebody being a hero, I always tell them the heroes are still over there.

MALCOLM BRABANT: Naval cadet Bridget Sheridan paid tribute, taking hallowed sand and offering a silent prayer.

BRIDGET SHERIDAN, Naval Cadet: I come from a military family, so just being here with the veterans and everyone here, it's a blessing, an absolute honor.

I have no words.

MALCOLM BRABANT: Because their deeds speak for themselves.

For the "PBS NewsHour," I'm Malcolm Brabant in New York.