DEFIANCE, Ohio -- Here's the house on Perry Street, the time-worn Colonial with the peeling paint and sprouted weeds. Karl Kissner still stamps out his cigarette on the porch before stepping inside, a show of respect for his long-since-departed grandparents.

"Don't smoke in there," he says. "Never could."

Here are the stairs leading to the second level, and Kissner must pause to point out that he was probably 30 years old before he was allowed to climb up them, and only then because his aunt needed him to help with the maintenance work.

And here, if you duck down and step through the entryway, is the attic, swamped in soot and, until mere months ago, packed to the rafters with more than a century's worth of family remnants.

This has become the most famous attic in America this summer, the place that made Kissner's relatives heroes to pack rats everywhere. For this is the place where Kissner made what one baseball card-collecting expert has called "the most significant find in the history of the hobby" -- a cardboard box filled with hundreds of baseball cards from early in the 20th century and estimated to be worth $3 million.

On Thursday, the first and most significant batch of those cards will be auctioned off by Heritage Auctions as part of the National Sports Collectors Convention. A set featuring the likes of Ty Cobb, Connie Mack, Cy Young, Christy Mathewson and Honus Wagner has already received bids in excess of $200,000 at Heritage's web site (ha.com), and a mint-condition Wagner card has received a bid of $150,000 on its own. Those online auctions will be completed in-person at the convention in Baltimore's Camden Yards.

And when they're completed, Kissner and his 19 cousins, who are splitting the pot evenly, will have quite a few more bucks in their bank accounts. And they each have an additional set with which they can do as they please down the road.

All because, long ago, Kissner's grandfather, Carl, the owner of a meat and sausage shop that sat just two blocks away at the corner of Fifth and Perry, put an unused box of promotional items away in his attic and likely forgot all about them.

"Thanks, Pop!" Karl says with a laugh.

And yes, he's laughing all the way to the bank.

But this story is about family bonds as much as monetary ones.

* * *

Jean Hench was 85 years old when she died last October. And the truth is, she left behind quite a mess.

"Aunt Jean," as she was known to Karl Kissner and his cousins, had inherited the home on Perry Street, which was built in the 1880s, after her mother and father passed, and she never really cleaned it out. In the basement, on the main level and especially upstairs, the boxes and dresser drawers were stocked with stuff -- letters, clothes, jewelry, antiques. When Karl would come over every so often to place mouse bait in the attic, he'd have to move several boxes just to get to the door. Jean just had this distinct inability to throw anything away.

That was her curse; it would become the family's blessing.

When Jean died, Karl organized three work weeks at the house. One in December, one in January and one in February. Any of the cousins who were interested in taking part in the cleanup and uncovering the many mementos held in the house were welcomed to do so. And at any given time in those weeks, seven or eight members of the family would be on site, pulling out another piece of history -- journals, turn-of-the-century dresses, calendars ... even a skull. One of Kissner's uncles had been in medical school and used it for research.

"Every family has one in their closet!" was the running gag.

The process of emptying this home of its artifacts might have felt like work if it wasn't so doggone fun. The cousins and their kids swapped stories, shared laughs and learned about their roots. They found everything from cold, hard cash to junk worthy of the trash.

But their biggest find didn't come until the very end.

* * *

It was Leap Day, an extra gift on the Gregorian calendar. A day for bonus opportunities.

Karl Kissner and his cousin, Karla Hench, had finally made their way to the furthest point in the attic from the entryway, past the heavy steamer trunk that had previously blocked access to this area. They moved a large wooden dollhouse and found boxes stacked alongside round tubs near the window. And when they opened the bottom box, they found the house's most pleasant surprise yet.

"There was a stack of 24 cards, tied with a string," Karl says. "The first one I saw was Miner Brown. He was loose on top. Then there was Cy Young, then Ty Cobb and then here's Honus Wagner. It's kind of that weird feeling of, 'Is this real?' Because they were really strange-looking in their style, their size."

For the moment, they put the cards aside, content to inspect them later. The box was actually sitting alongside several others as Karl's cousin, Eric, loaded up a truck to take to the dump.

"Does this one go?" Eric asked, pointing to the box filled with cardboard gold.

"No," Karl said coyly, "we want to look into that one a little more."

Kissner is a big baseball fan, keeping particular tabs on Defiance natives Jon Niese and Chad Billingsley. But he's hardly a card collector. He was pretty sure these cards were the real deal, but he couldn't rule out the possibility that they were reprints of some sort. So he packed up the eight cards that seemed to him to be the most significant, put them in a FedEx overnight package (insured, of course) and sent them to the first of three auction houses that got back in touch with him after his initial contact.

Chris Ivy, director of sports auctions at Heritage Auctions, will always remember that March day when the package arrived at his Dallas office and he and coworker Pete Calderon inspected its contents. Kissner attached a note instructing them to give him a call before opening the package, because he wanted to hear their initial reaction for himself.

That reaction?

"Oh, my God."

Kissner knew he had the real thing.

"Thank God for Leap Day," he says.

* * *

The "E98 series" was a set of 30 cards, printed in 1910 and handed out with caramel candy. It featured 17 eventual Hall of Famers. Because Kissner's grandfather owned a sausage shop that sold candy -- shipped in those round tubs discovered next to the box of cards -- it stands to reason that he had received this as a promotion and simply never doled them all out.

Prior to the Defiance discovery, only about 625 of these cards were known to be in existence.

The box found in the attic had about 700 of them.

"The E98s were typically packaged with candy, and it would stain the cards," Ivy says. "But these were in pristine condition. They were as sharp as they were the day they were packaged up, and the colors were as bright as they were 100 years ago. This would have been a great find if it was limited to the eight cards they sent us on that first day. But when they told us they had 700 more that were just like it, our jaws hit the ground."

How did the cards remain in that condition over more than a century of sitting in that cardboard box? Well, the key, it appears, was the cardboard itself. The cards were printed on a no-acid cardboard, and so their chemical composition did not compete with that of the box. And because the attic was dry, the cards held up about as well as if they were pieces of wood.

"In the basement," Kissner says, "they would have drawn moisture and stuck together."

Ivy and Calderon traveled to Defiance to get the rest of the cards so that they could properly document them, secure them and have them graded. And for months, the only people in Defiance who knew about what was anonymously called the "Black Swamp Find," referring vaguely to the wetlands of northwest Ohio, were Karl and Karla.

It wasn't until June 1, once the value of the cards was estimated, that Karl gathered all his cousins together and, with Ivy and Calderon on hand, let them know the significance of what was found in that attic.

"Obviously word travels fast that something was afoot," Ivy says. "I think they knew Karl had found something in the house, but they had no idea what it was. Karl told them the story, and when he mentioned the name Honus Wagner, there were gasps."

* * *

Gasps were the general response when the news went public.

The family had debated whether to remain anonymous or share such an amazing story with the world, and well, you know how that worked out. The Associated Press broke the story on the day of the All-Star Game, and nothing in Kissner's world has been normal since. As the official family spokesperson, he's done countless radio hits and newspaper interviews, and he and Karla were flown to New York to appear on "The Today Show" a couple weeks back.

Perhaps the greatest tribute to the viral nature of the story came when Pulitzer Prize-winning political cartoonist Walt Handelsman whipped up a sketch of President Obama, clutching a newspaper detailing the Defiance find and telling his strapped budget staff, "If anybody needs me, I'll be in the attic."

Though the first batch of cards is now up for auction, the rest of the offerings will be staggered over the years. The family wants to be careful not to flood the market, lest they hurt the value not only of their own cards but also those owned by others. Kissner says he is sensitive to those who might have a certain financial dependence on the value of previous E98s or cards featuring players in this set.

"I equate this to Pandora's Box," Kissner says. "A thing of great beauty and value. But once opened, it has a tendency to destroy and has a tendency to cause greed. In this family, we weren't raised that way."

The find has been a source of fascination. After all, how many of us hold on to every toy or trinket, thinking, often naively, that it "might be worth something someday"? How many of us rue the day our mother tossed our baseball card collection in the trash? How many of us wish some stroke of luck or fate -- a lottery ticket or a long-lost wad of cash -- could magically bring us some financial flexibility?

So the story resonates for more than just the hardcore hobbyists, and it's brought unprecedented attention to this tiny town of about 16,000 people.

"It's just one of those things where, if you put everything together and you know the family, you can understand how it happened," says city administrator Jeff Leonard. "People who don't know the town might say, 'How could that happen?' But it's not all that far-fetched, because the house has been in the family so long."

The family restaurant, Kissner's, which Karl runs, has also been in the family forever. It first opened in 1928 and recent renovations have preserved its antique interior.

So Karl and his family members, many of whom will be in attendance at the auction, have an appreciation for history, certainly. But they also have an appreciation for each other, strengthened by the shared experience of uncovering a century's worth of family heirlooms and that now-famous box of gold.

"I think, for this family, sure, the value is nice," Kissner says. "But I think the fun and the memories are worth more to us. Because it's just been a ball."