(USA TODAY by Janet Kornblum) The German submarine lies where it was felled in 1942.
For 62 years, it has rested 270 feet beneath the surface of the Atlantic, 150 miles off the coast of New England and south of Nova Scotia, just across international waters into Canadian territory.
This month, a team of deep-sea scuba divers from the Canadian-based TV series The Sea Hunters found the wreck, encrusted with sea life and still sealed with the remains of 49 German sailors entombed within.
On July 3, 1942, U-215 was on its way to mine Boston Harbor when its captain attacked and sank the U.S. liberty ship Alexander Macomb, part of an allied convoy. The British warship HMS Le Tiger counterattacked with a series of depth charges.
U-215 was presumed sunk, but during World War II, it wasn't always possible to confirm a kill. U-boats sometimes "faked" their demise by lying on the ocean floor and intentionally leaking debris to the surface. So there always was a possibility that the U-boat could have survived and gone on to other missions.
But the Sea Hunters crewmembers laid to rest that possibility when they found the sub after consulting records and talking with locals - including fishermen who often found their nets snagged in the area of the wreck.
The discovery will be broadcast in Canada later this year and possibly in the USA.
U-215 was one of six U-boats of its kind, outfitted with special tubes that could hold mines. Four of the five tubes are still sealed.
Whether U-215 would have succeeded in mining Boston Harbor will never be known.
But Mike Fletcher, who led the dive team, says the experience reminded him of the viciousness of the war and the terror caused by U-boats.
"To me, the U-boat represented everything that was ugly about the Nazi political party," Fletcher says.
Diving so deeply where it is so frigid and dark, and where Fletcher had to struggle against strong currents, added to the eeriness.
"It all comes together to paint a really, really - I use the word creepy, but there's got to be a better adjective than creepy - picture. Creepy and at the same time profound. I don't know really how best to describe it."
Fletcher is not the only one to feel this way about U-boats - and for good reason.
The subs terrorized the USA's Atlantic Coast, especially at the beginning of the war.
There were official blackouts - when homes in neighborhoods were required to shut off their lights by specified curfews - on the West Coast right after the attack on Hawaii's Pearl Harbor on Dec. 7, 1941. But blackouts were not required on the Atlantic seaboard until later in the war.
The result was deadly. Ships were lit at night by the coastal lights, and submarines were taking them out with ease.
"It was almost like shooting in an amusement park," says military historian Edward Sheehy, associate professor of history at La Salle University in Philadelphia.
U-boats came so close to the Eastern seaboard "that people could look out from their beach house and see ships burning."
The fact that U-boats were basically invisible made them psychologically even more terrifying. "These extraordinarily lethal killing machines could appear and disappear in a moment's notice with no warning," says Robert Kurson, who wrote the just-released Shadow Divers, a true-life thriller about a deadly expedition of a U-boat off New Jersey.
Though they were deadly for the Allies, they were often a death sentence for the sailors aboard. There were 1,171 U-boats commissioned during World War II, says Jak Showell, a naval historian from Folkestone, England, and member of the U-Boat Archiv in Germany. But only 859 U-boats were deployed for battle, and three-fourths of them - 648 - were sunk or captured at sea, Kurson says. And only 321 U-boats actually attacked and caused damage to allied ships, Showell adds.
With so many U-boats sunk, many remain unseen on the ocean bed. About 21 U-boats lie off the Eastern seaboard and Gulf of Mexico, and about six have been found, says Barbara Voulgaris, a cultural resources specialist with the U.S. Naval Historical Center.
All military ships found at sea remain the property of the country of origin. So the U-boats found in the Atlantic belong to the German government.
Its policy has been to leave the boats as they are. The sites are considered wartime graves.
American archaeologists also strongly denounce those who would loot the submarines for the Nazi memorabilia within.
Fletcher's team will reveal the coordinates only to government officials and people who need them - families of the sailors on U-215.
"We definitely have a grave site. We definitely have to be respectful of that, but at the same time, we can't forget that those guys were our enemy and they were sent here to kill our friends and our allies," Fletcher says.
"So you can forgive them and get over it, but you can't forget."