In November 1944, or maybe it was December, a German fighter plane crashed down on the Kristiansen family farm in Denmark.

That was one of the many tales told by 14-year-old Daniel Kristiansen’s great-grandfather. His children and grandchildren who heard the story wondered whether it was true, or at the very least embellished. Grandpa, after all, was known to enjoy a good yarn.

But Daniel and his father, Klaus Kristiansen, decided there was no harm in searching for the plane with a metal detector. A schoolteacher had assigned the teen a project involving World War II. Why not include a bit of family history?

Equipped with the detector, the pair recently scoured their farmland in Birkelse, in northern Denmark. Klaus had lived on the land for four decades.

To their surprise, the detector beeped. The father and son began to dig. Handheld spades turned up little but roots and soil. Undeterred, the Kristiansens acquired a backhoe.

Some four yards down, they hit metal. And then they found human remains.

“At first we were digging up a lot of dirt with metal fragments in it. Then we suddenly came across bones and pieces of clothes,” Klaus Kristiansen told CNN. “It was like opening a book from yesterday.”

Three-fourths of a century later, the schoolboy’s relative was vindicated. As Klaus said his grandfather told it, around Christmastime in 1944, the Kristiansen ancestor was baking cookies when a German fighter plane smashed into the boggy Danish soil.

But even Daniel’s great-grandfather had doubted the plane still remained, believing that a German force, occupying Denmark, removed the debris. But the wreckage persisted. Grass, for grazing cattle, grew over the site, obscuring the plane from sight and mind.

“I hoped we might find some old plates or something for Daniel to show in school,” Kristiansen said to CNN.

What the father and son discovered instead was a Luftwaffe Messerschmitt Bf 109, broken into, by Kristiansen’s estimate, 2,000 to 5,000 pieces. A few bits of debris, like the Daimler-Benz aircraft engine, remained in large sections.

“He was telling a lot of stories, my grandfather,” the elder Kristiansen told the BBC. “Some of them were not true, and some of them were true — but this one was true. Maybe I should have listened to him a bit more when he was alive!”

The Messerschmitt’s wreckage served as its pilot’s grave for more than 70 years. The Danish father and son found a few objects with the fighter pilot’s remains: a pair of old coins, three condoms — still wrapped —  his wallet, and ration stamps good for the canteen at the nearby Aalborg air base, which Germans had captured from Denmark in 1940 during one of the world’s first paratrooper invasions.

Included among the pilot’s personal effects, still tucked in his pocket, was a book.

“Either it was a little Bible or it was ‘Mein Kampf.’ We didn’t touch it, we just put it in some bags,” Kristiansen told the BBC. “A museum is now taking care of it. I think there’s a lot of information in those papers.”

The Historical Museum of Northern Jutland took charge of the remains. The museum’s curator told CNN that the pilot identification papers remained intact, so it may be possible to determine the man’s name. Kristiansen said he hoped the pilot could receive a proper burial in Germany.

Camera crews came to view the site. So, too, did explosives experts, to remove the fighter’s old — though possibly still dangerous — ammunition.

The Messerschmitt Bf 109 was one of the first true fighter planes of World War II. Named after German aviation engineer Wilhelm “Willy” Messerschmitt, the plane made up the core of the Nazi air force.

In the 1940 Battle of Britain, the planes famously tangled with British Supermarine Spitfires. Some historians believe the Me-109’s cannons probably killed more enemy pilots than any other fighter plane guns in World War II. The aircraft was produced in record numbers: Including 109s ordered by countries other than Germany, more than 33,000 of the planes were built, according to Washington state’s Museum of Flight.

Messerschmitt pilots crashed or were shot down across Europe, from a British golf course in the west to the Russian front in the east. The Danish father and son were not the only people to make a remarkable discovery involving one of the German fighters. In 2003, aviation archaeologists pulled such a plane from the bottom of an icy Russian lake.

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