Designed to liberate Nazi-occupied Europe, "Operation Overlord" signaled the turning point of World War II.
Watching from one of the boats was 18-year-old Jack Schaffer.
"That was kind of impressive," said Schaffer, 72, who now lives in Hagerstown. "I did wake up to the fact that we were going into the war."
Many did not know they were going into combat until shortly before "D-Day."
Overstating his age by two years, then-16-year-old Kenny Jones enlisted in January of 1941.
"I wanted to go into the service," said Jones, who now lives in Funkstown. "I dropped out of school and I had to do something."
The boats were loaded for the D-Day invasion several days prior to the storming of the 50-mile stretch of Normandy's beach.
The troops knew little about the battle they would soon be fighting.
"All we had heard (was) we were going to be landing on Normandy," Schaffer said. "We didn't know what part."
Jones was told he was going to France to take the beach and his objective was to liberate St.-Lo in about three days, a task that actually took closer to a month.
"They try to paint a picture that's kind of pretty," Jones said. "But really, you didn't know and he didn't know."
Severe weather delayed the attack until June 6. Early that morning, planes bombed the beach for at least two hours to clear a landing site for the boats, which began arriving at 6:30 a.m.
That was enough at Utah Beach, where the 4th U.S. Division landed.
"My main concern was drowning," said Schaffer, who carried six 81mm mortars to the shore.
From England, Baker heard reports of the battle. "The reports we heard weren't good."
Rough terrain at Omaha had rendered the bombings ineffective. And Jones recalled what history has proven - that there was a much higher concentration of German troops than intelligence had indicated.
The 116th Infantry, which had gone in before Jones' division, was slaughtered. "We were scheduled to in three hours after it started, but they got wiped out and we were sent in within the hour," he said.
He said the scene on the beach was one of confusion and disorder. Whenever he looked to either side, he saw things exploding.
Jone's mortar unit was attached to a rifle platoon. Those from the platoon would tell him where they thought Germans were firing from and he would aim his 60 mm mortar in that general direction.
"You couldn't see much of anything," he said.
Many of those involved were in their teens or early twenties.
"It didn't occur to me I was that young," said Schaffer, who was 18 when he landed at Utah.
Months of training had most of the soldiers reacting automatically, Jones said. Some were shaken, but none that he saw froze completely.
"I've seem them bawl, I've seen them crawl," Jones said. "But there was always someone there to pick them up."
That first day killed 2,500 Allied soldiers, far fewer than the 10,000 that officials had forecast. Those remaining had gained a small foothold in Europe - with those at Omaha having pushed only two miles inland.
Baker eventually joined the soldiers at Normandy as a "litter bearer," carrying the injured off the battle field to a makeshift hospital.
Baker carried a little silver Bible at all times, in a pocket over his heart.
"I never thought I'd come back," he said. "I know a lot of guys who didn't."
About 11 months after D-Day, the Germans surrendered.
Jones, who was injured twice, lost his brother to the war. Schaffer was not able to return for the funeral of his father, who died of cancer while he was abroad.
"When I left Detroit, that was the last time I'd seen my dad," Schaffer said.
Despite the sacrifices, veterans say the war was necessary and they're proud to have been a part of it.
"We had to go against Hitler," Jones said, "because if we didn't go over there, he was coming over here."