MARS BLUFF, S.C. (AP) — Ella Davis Hudson remembers stacking bricks to make a kitchen to play house. The next thing she knew, the 9 year old was running down the driveway, blood streaming from the gash above her eye.

She doesn't remember the actual blast from an atomic bomb.

Sixty years ago, on March 11, 1958, an Air Force bomber dropped a nuclear weapon on a farm in the rural Mars Bluff community outside Florence. The radioactive payload either wasn't loaded in the warhead or didn't detonate — the stories differ.

But the TNT trigger for the bomb blew a crater in Walter Gregg's garden some 24 feet deep and 50 feet wide. The blast shredded his farm house about 100 yards away. Hudson, a cousin, had been playing with two of Gregg's children in the backyard.

The atomic warhead would have been 30 kilotons — twice as powerful as the bomb that devastated Hiroshima in World War II. Florence, five miles away, would have been obliterated. Most of the rest of the 30,000 residents of Florence County would have been wiped out or sickened by radiation.

You'd think the crater site would be one of those ghoulish attractions that become a heavily promoted tourist site. But today it sits almost in obscurity on private property, in the woods at the edge of the backyard of a home in a modest neighborhood near Francis Marion University.

An information kiosk and a wooden silhouette of the 10-feet-tall, 7,600-pound bomb stand near what's left of the hole, which is silting in. Hurricane debris limbs have been tossed along its rim and a few Pepsi and Bud Lite cans are scattered around. There's no sign from the road to show it's there.

The stream of curious visitors is steady, though. You can almost tell the season by them — Canadian license plates in the spring and motorcycle groups in the summer, neighbor Mary Cantey said.

The neighbors are amused. They've talked about putting up a homemade sign to point it out, but it's too much fun to watch people try to hunt it down, said Cantey, who can see the impact site from her porch.

"If I see a car come around the neighborhood twice, I know they're looking for it," she said.

The tale, on the other hand, is anything but fun.

You don't want to think of trained crews bobbling atomic bombs. But the Mars Bluff incident is one of about a dozen unplanned drops that took place in the 1950s before the military decided not to carry nuclear warheads on training runs.

They called the lost bombs "broken arrows."

The era was the dawn of the Cold War, when atomic bombs were still as incomprehensible as they were horrifying. The threat was immediate. There was no real defense. School children ran through drills where they hid under their desks — "duck and cover" — in case of an attack.

Just a month before the Mars Bluff incident, a bomber dropped a hydrogen bomb somewhere off Tybee Island, Ga., after colliding with a fighter jet during training. A nuclear explosion from it would have been 100 times more powerful than Hiroshima.

That bomb has lain buried deep somewhere in the ocean-bottom muck for more than a half-century.

Typically during training runs the bombs carried uranium but not the capsule needed to detonate it, although in Congressional testimony in 1966 the acting secretary of defense said four of the missing bombs did carry the capsule, including the Tybee bomb, according to a later CBS News report.

The testimony itself was later recanted — just one indication of how secretively the military dealt with mishaps.

When Hudson came to her senses that day in 1958, she was running frantically, with fallen electric lines singing around her.

Helen Gregg Holladay, one of the daughters Hudson was playing with, remembers getting up from the ground to find an entire stand of pines, where the 6-year-old had just climbed down from her tree fort, flattened.

Hudson had been struck in the forehead by a brick. Holladay, somehow, was uninjured.

The adults piled the kids into a car and raced to a hospital, with Hudson's gaping wound wrapped in the apron she had been playing in.

Hudson remembers the speedometer reading 80 mph and her yelling at the driver to slow down.

At the hospital, two odd things happened for a little country girl: Everybody wanted her to pull off the apron so they could take photographs and a doctor waved a Geiger counter over her.

The story told in Mars Bluff is that the bomb was launched inadvertently, bumped loose from a B-47 when the plane hit an air pocket as a crew member leaned over the launch trigger to check it.

The military never officially said. Its spokespeople insisted early and often the bomb wasn't armed and there was no danger of nuclear detonation.

But one of the pilots made a distress call saying they had jettisoned "hot cargo," or an atomic bomb. The three pilots, said to be on training mission out of Savannah and cruising at 15,000 feet, were re-assigned overseas for seven years. When they came back, they went to see Walter Gregg.

"They told my daddy everything was aboard," Holladay said. "It was a totally different story than what the government put out."

For the next 25 years, she said, military craft flew overhead the farm checking for radiation.

No one died or was seriously injured in the Mars Bluff blast. But the Gregg family came away with little more than the clothes on their backs.

Walter Gregg eventually sued and was awarded $36,000, according to the exhibit at the Florence County Museum. That wasn't enough to rebuild the house, much less replace the possessions lost or stolen in the aftermath, Holladay said.

"My daddy resented it all his life."

One smile-inducing postscript to the story: The Greggs later appeared on the television show "I've Got a Secret" and stumped the panel trying to guess what the secret was.

In 2008, making an effort to recognize the event, county historians erected the markers at the site and held a commemoration ceremony attended by about 100 people.

"It's not many towns that can say they had an atomic bomb drop and nothing (deadly) happened," said Marshall Yarborough, the Florence County Historical Commission chairwoman.

Internet-recirculated reports of the ceremony and flurries of social media postings continue to spur the curious to come see the site.

The historical commission is seeking to buy that wedge of the property from the owner to turn into a park, Yarborough said. But no luck so far.

Hudson carries the scar on her forehead to this day. She doesn't dwell on the incident or often talk about it. Out to dinner once, she and her husband, Knapp Hudson, surprised a table of Air Force officers who were talking about the Mars Bluff bomb by introducing her to them.

But mostly, "it's just too fantastical to tell people," she said. "It's like a chapter in your life you just close."

Holladay will still pause to take a breath when she talks about it.

"I think I'm lucky to be alive," she said.

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Information from: The Post and Courier, http://www.postandcourier.com