'I just kind of put my camera above my head . . . and clicked a picture . . . and when I came back, I was a very famous photographer." The voice you hear in the archive of the International Center of Photography is a Carpathian mumble: the only known recording in existence of Robert Capa's voice. Incredibly, it turned up for sale on eBay recently and was discovered there by a Capa curator at I.C.P. who had been searching for it for years. Here was Capa in October of 1947 on New York's most popular radio show, Hi Jinx, with Tex McCrary and Jinx Falkenburg. On the air, he was very clear about the moment he believed had changed his life. "That camera which I held above my head just caught a man at the moment he was shot. . . . That was probably the best picture I ever took." Capa is referring to his most well-known—and perhaps most controversial—image, the dramatic photograph taken September 5, 1936, called The Falling Soldier. Who hasn't seen the picture? The Loyalist volunteer, in his white shirt with sleeves rolled up, stands with his rifle and is gunned down, the impact causing him to collapse backward.

In the 1970s a British journalist challenged the authenticity of the photo, saying it was staged, a claim that has been debated. Another theory suggests that in fact Gerda Taro—the woman responsible for his transformation from Endre Friedmann into Robert Capa, mysterious "American photographer"—took the shot, an assertion that Capa scholars strongly dispute. Taro would die in Spain in 1937, the first female correspondent to be killed in combat. Capa never recovered from her loss. "Capa detested the picture. He did not want to have anything to do with an image that exploited death," Morris told me.

Now, at dawn on June 6, 1944, Capa was on the deck of the Chase. Fuller, just behind on the Henrico, took out a condom and put it over the end of his rifle, desperate to keep it from getting wet. In the gray light stood the great Allied fleet off Normandy's five invasion beaches, in silhouette. No one was prepared for the noise—the grinding of hundreds of engines, bombers flying overhead, the screams of men loaded with as much as 300 pounds of equipment falling off assault boats into the high surf, as author Cornelius Ryan observed in The Longest Day. Capa and Fuller stood frozen as the bullhorns blared, "Keep in line, keep in line! Don't forget the Big Red One is leading the way."

Troops jammed the rails of the Chase, waiting to climb down the nets into the roiling assault boats, bobbing up and down on the giant swells, while others slipped on the ladders with their guns, shovels, and bedrolls. Frigid water filled the boats, and the seasick were covered in vomit, their own and everyone else's. Trying to take in the scene, Capa blocked out the sound. "Two thousand men stood in perfect silence," he later wrote. "H-hour," the moment of invasion, was set for 6:30 A.M., and the waves of landing craft were set to launch at precise 15-minute intervals. The 3,000 men in the first wave had little idea they would face an avalanche of mines, rockets, and flamethrowers. No one had predicted that the Allied bombers would get blown off course and not knock out the Germans' beach defenses, or that one day earlier a crack division of German troops would move to Omaha for practice maneuvers.

The coast of Normandy was miles away when the first sounds of popping forced Capa down in his assault boat. In front of him, a mass of crossed steel girders formed an impossible barricade that ran the entire length of the Normandy coast and was loaded with as many as six million mines Hitler had ordered placed there with slave labor. As Capa got closer, massive explosions rocked the shore. Smoke rose from every side in vast plumes. Men, on fire, tried to escape the inferno. Jumping up, Capa stopped to take his famous picture of the platoon of men from his assault boat wading into the carnage that awaited them in the water. Mistaking his hesitation, the boatswain kicked Capa in the rear.

"Bullets tore into the water around me," Capa wrote. The beach was 100 yards away, and the steel barriers rose like the remains of a ghostly city in a mist. Capa ran through a barrage of shells with his Contax and waited behind the nearest steel obstacle. "It was still very early and very gray for good pictures, but the little men dodging under the surrealistic designs . . . very effective," Capa wrote. He clung to the pole, his hands shaking, shooting picture after picture. In front of him, on the beach, rose a half-burned amphibious tank. Capa dropped his Burberry raincoat into the water and made for the tank. All around him bodies floated in a sea of blood and vomit. It was not possible to retrieve the dead, and the living were unable to advance. Crawling on his stomach, he joined two friends, an Irish priest and a Jewish medic, and then began to shoot with his second Contax. "The foreground of my pictures was filled with wet boots and green faces," he wrote.

Suddenly, from the boil of the red ocean, Capa caught the face of a young, helmeted soldier under fire, manning his position half submerged, with the eerie towers of German obstacles behind him. Capa raised his camera and caught what would emerge from Omaha Beach as arguably the iconic image of the war. "I didn't dare to take my eyes off the finder of my Contax and frantically shot frame after frame." Then his camera jammed. In front of Capa, hundreds of men were screaming and dying, body parts flying everywhere. Sam Fuller, on the landing boat behind Capa, temporarily lost his hearing from the noise. In his memoir he describes Capa taking out a telephoto lens to shoot a German officer on the hill with his hands on his hips, shouting orders.

"I held my camera over my head. . . . I stepped into the sea between two bodies . . . and suddenly I knew I was running away," Capa wrote. As he reached a medical transport boat, he felt an explosion and found himself covered with feathers from the down jackets of the men who had just been blown apart. As the boat pulled back from the beach, the skipper cried; his assistant had literally been exploded all over him.

On the transport back to Weymouth, as Capa helped to load stretchers, the messboys in their white jackets and gloves, now covered in blood, were sewing up the dead in body bags. Capa got out fresh film to take one last shot. He used his Rolleiflex to record an emergency plasma transfusion on the deck and then collapsed. He later awakened in a bunk with a piece of paper around his neck: "Exhaustion case. No dog tags." The total time Capa spent on Omaha Beach was approximately 90 minutes.

At Weymouth, Capa positioned himself so he would be ready to photograph the medics coming for the wounded. Instead, when the bow doors opened, there was another Life photographer, David Scherman, waiting to capture the faces of the injured. Scherman hugged him and took the picture of Capa with his cigarette in his hand, his helmet at a jaunty angle, and a triumphant smile on his face. Capa scribbled a note to Morris telling him that the action was all on the 35-mm. rolls, then got on board the next transport back to Normandy. Capa, who prided himself on not knowing what he shot, knew exactly what he had that day: four rolls full of what could well be the most stirring images of warfare ever created.

I've come to Normandy with John Morris on a sunny November day to rewalk Capa's Omaha. Morris, dressed elegantly in tweeds and still indefatigable, has made a one-man industry of recounting the story of Capa at D-day, reminding the world of the moral power of great photography and, as well, the arbitrary nature of who and what survive. Morris has visited Normandy many times, and June 6 is etched permanently in his mind. As the news of the invasion swept the wires, Morris, like the entire world, was in a fraught state. "All that day, I waited and waited. I heard nothing. Everyone in the darkroom was poised. All that night, I did not sleep, waiting for Capa and his film."