Doyle Rice

USA TODAY

For decades, the dead lay silently, undisturbed and resting on the cold, dark ocean floor.

Now, for the first time, explorers have scoured the Atlantic Ocean graveyard, the site of some of the battles fought closest to the U.S. mainland during World War II.

In 1942, Allied and German navies dueled in the Battle of the Atlantic, in "arguably the largest battlefield in human history," said David Alberg of NOAA's Monitor National Marine Sanctuary, which led the expedition.

The war arena stretched across the north and south Atlantic, from Iceland to southern Africa as German submarines sank hundreds of Allied ships.

Some skirmishes came within just a few miles of North Carolina's Outer Banks, where a NOAA submersible dived for the past few weeks, taking a close look at the wrecks of the Allied Bluefields freighter and the German U-576 submarine. The two vessels, submerged under 750 feet of seawater since 1942, weren't spotted by sonar until 2014.

NOAA's excursion using manned submersibles marks the first time in nearly 75 years anyone has laid eyes on the U-576 or Bluefields, Alberg said.

"These two ships rest only a few hundred yards apart and together help us interpret and share their forgotten stories,” said Joe Hoyt, expedition chief scientist with NOAA.

On July 15, 1942, a torpedo from the German U-576 sub sank the Nicaraguan-flagged Bluefields and damaged other ships. Minutes later, Allied charges from Navy seaplanes returned fire and sank the sub.

The U-576 likely includes the entombed bodies of 45 German sailors. All the seamen aboard the Bluefields were rescued before it sank. Others weren't so lucky: Some 1,600 men, mostly Allied sailors and merchant mariners, died in battles off the North Carolina coast. Many who survived are now in their 90s.

“We have a narrow window of time for this before the last of the World War II veterans pass away,” Alberg said.

The sub is the property of the German government, which declared two years ago it has no interest in recovering any wreckage or the bodies, according to LiveScience.

NOAA hopes its mission will "preserve this little known chapter of American history" and "help memorialize the sacrifice of the men and women who were lost in what is truly one of the only World War II battlefields on the U.S. East Coast," Alberg said.

Just as Gettysburg is memorialized as a Civil War battlefield, this ocean-based war arena should receive the same reverence, Alberg said. NOAA could expand the close-by Monitor National Marine Sanctuary, site of the wreck of the famed Civil War ironclad ship, to include the German sub, the Bluefields and other shipwrecks.

NOAA’s Office of Ocean Exploration and Research, the University of North Carolina’s Coastal Studies Institute and the Bureau of Ocean Energy Management participated in the mission.