Many Americans probably have never heard of Guadalcanal, the Kasserine Pass, Anzio, the Hurtgen Forest, Peleliu, the Coral Sea, Tarawa or Ploesti.

But they have heard of D-Day, as they know about Pearl Harbor.

Today is the 70th anniversary of the allied invasion of France during World War II, in the operation that has come to be known as D-Day. The event has become an icon of American involvement in the war, representative of battles such as those listed above and many others.

For that reason and because of its individual significance as the death knell for Hitler’s regime, D-Day merits the attention Americans give it.

Many in Europe, especially in countries liberated from Nazism by the allies, also celebrate D-Day. There, in cemeteries where American soldiers killed in the war lie, U.S. flags decorating graves often stand beside the French Tricolor.

Few Americans have personal memories of what happened that day. Fewer still were part of the Greatest Generation serving in the military during World War II. And only a relative handful, now in their 80s and 90s, were at the Normandy beaches that day in early June, 70 years ago. Their numbers dwindle with each passing year.

It is difficult for many to imagine the carnage of World War II. Yet for a time on the morning of June 6, 1944, the very edge of the English Channel was tinted red from the blood of Americans and our allies. Acts of extraordinary heroism were common.

While there was some doubt the invasion would succeed – commanding Gen. Dwight Eisenhower actually pre-wrote a statement taking on himself the blame for a failure – there never was the slightest reason to believe the allies would not prevail in the end.

Much has been written about why that is so. American industry, technology and resources have been cited. But the battle in Normandy made it abundantly clear that what leaders in German and Japan had to fear most was American soldiers, sailors, Marines and airmen. The odds were against them on D-Day – yet they won the battle through their raw courage and determination, and were on their way to Berlin.

Again, comparatively few of them are among us today. Of the 16,112,566 million Americans who served in uniform during the war, only about a million survive today.

So D-Day is a time to think about history and an occasion to celebrate victory in an inarguably just war.

But today, it also is an opportunity to marvel at the Greatest Generation -and be grateful for them.