The exploits of D-Day (search) have long been legend: the storming of the beaches, parachute drops into enemy territory. But 60 years later, the number of dead is still unclear.
The chaos of battle and the vast scale of the assault thwarted attempts then -- and now -- to tally how many thousands were killed in the June 6, 1944, landings that sped Nazi (search) Germany's defeat.
Bodies disintegrated under bombs and shells. Soldiers drowned and disappeared. Company clerks who tallied casualties were killed. Records were lost.
"Landing crafts were hit," said Ivy Agee, an 81-year-old from Gordonsville, Tenn., who fought on Omaha Beach. "Bodies were flying everywhere. There was blood on the edge of the water, the beach was just running with pure blood."
Historians say a definitive death toll will likely never be known. Even now, the Normandy (search) soil for which soldiers fought so bitterly offers up new bodies.
"Now and then, construction work unearths bones and skeletons from soldiers. This happens fairly often," said Fritz Kirchmeier, a spokesman for the German organization that tends the 80,000 graves for German soldiers in Normandy.
Casualty estimates for Allied forces vary, but range from 2,500 to more than 5,000 dead on D-Day. Adding to the confusion is that D-Day books and histories often count wounded, missing and troops taken prisoner.
On its Web site, the D-Day Museum in Portsmouth, England, says an estimated 2,500 Allied troops died. The U.S. Army Center of Military History (search) in Washington, D.C., numbers 6,036 American casualties, including wounded and missing. The Heritage Foundation in Washington estimates 4,900 dead.
"It's very difficult to get accurate figures. People get buried. Bodies disintegrate. Evidence of the deaths disappeared. People drowned," said John Keegan, author of "Six Armies in Normandy: From D-Day to the Liberation of Paris."
He estimates 2,500 Americans and 3,000 other Allied troops died on D-Day.
More than 19,000 civilians in Normandy also died in Allied bombing before and after D-Day to soften up German defenses. And Allied air forces lost nearly 12,000 men in April and May 1944 in operations ahead of the invasion, the D-Day Museum says.
Even as the ranks of veterans who survived the assault and the push into Germany thin with time, work on tallying the dead continues.
Carol Tuckwiller, director of research at the National D-Day Memorial Foundation (search) in Bedford, Va., has spent four years combing through government, military and cemetery records for names of Allied dead on D-Day. She hopes to have a figure by next year.
"We feel like we're probably going to end up with a total of about 4,500 fatalities for both the Americans and Allied countries. Right now, we have about 4,200 names confirmed," she said. "Of course we realize we may never be 100 percent complete."
In all, some 160,000 men invaded Nazi-occupied France in the first wave, in three paratroop and six infantry divisions, tank and commando units. The invasion fleet was the biggest armada in history, with more than 5,000 ships and landing craft. That more troops were not killed is testimony to the planning, training and overwhelming firepower of the Allies.
Sir Winston Churchill (search), Britain's wartime prime minister, "said to his wife before going to bed that he was afraid that when they woke up, more than 20,000 people would have been killed," said Andrew Whitmarsh, the D-day Museum's military historian.
"The low casualty rates show the success of the Allied plan of attack."
Calculating German casualties is even harder. The D-Day Museum says the number is not known but is estimated at 4,000-9,000. Kirchmeier at the German graves commission said many records were destroyed in the Allied bombing of Berlin.
D-Day marked only the start of the battle of Normandy, which claimed many more lives as troops fought in the region's hedgerows over the next three months.
More than 425,000 Allied and German troops were killed, wounded or went missing, the D-Day Museum says. The American Cemetery overlooking Omaha Beach (search) holds the remains of 9,383 servicemen and four women, their white gravestones a permanent reminder of war's terrible costs.
"If you forget what happened here then you're never going to improve things. It's never going to get any better," Donald Null, an 80-year-old veteran from Frederick, Md., said as he visited the American Cemetery. "You must keep it alive."