Philadelphia, for all the hipster resurgence of its Center City, remains one of those places where what was is more important than what is.

The soaring Comcast Technology Center, Vernick Food and Drink, and "Trust the Process" are great civic additions, but for most of us - not to mention the rest of the world - they'll never overshadow Independence Hall, Pat's, and "E-A-G-L-E-S."

What's been most surprising in doing this column for the last 3½ years is how often I've been surprised, how often I've discovered that things happening elsewhere in sports had roots that reached back to Philadelphia.

A recent Forbes article provided another example. It told the story of a 90-year-old Tennessee woman who discovered in her attic hundreds of unopened baseball card boxes from the 1940s and 1950s. Despite a slump in card prices, their worth was estimated at more than $1 million.

The most valuable, it turned out, had been produced by a company in Philadelphia. One box of cards, manufactured by the Bowman Gum Co. in 1948, was now worth $500,000.

Philadelphia was once the hub of both gum and baseball-card production. In the years immediately after World War II, Bowman's Stenton Avenue factory ran virtually nonstop, feeding what in those early days of the baby boom had become a national obsession. In 1950 alone, the company manufactured and distributed more than 200 million baseball cards.

While it wasn't the first with the idea, Bowman popularized the concept of combining trading cards and gum in a pack, a marketing trick emulated by such future local competitors as Olney's Fleer and Havertown's Philadelphia Chewing Gum Corp.

The first trading cards appeared in the 1880s as tobacco-product premiums. Companies found that by including 2¾-inch cardboard images of prominent athletes, actors, politicians, and military men, they could sell more cigarettes. Gum producers got the message.

Bowman's was founded here in 1927 by Jacob Warren Bowman, a flamboyant gum salesman from New Mexico. He married five times and, according to Dave Jamieson, the author of a book on baseball cards called Mint Condition, his Philadelphia office resembled something Ian Fleming dreamed up.

"The walls were covered with mirrors and he used an electronic switch to buzz in visitors. He would throw another switch to open a hidden door to his conference room, where there was a cocktail lounge and bar."

Since the 1930s, Bowman had been including cards picturing various American heroes with his gum. But in the '40s, when interest in sports - especially baseball - intensified, he ramped up and started printing numbered sets of baseball cards.

Soon they were far more popular than the gum.

That Forbes story tickled something deep in my psyche. Something about the Philadelphia card producers it mentioned, Bowman and Fleer, rang a familiar chord.

When I did a little research and saw the address of the Fleer factory, I knew why. Fleer's plant - a long, brick building along the railroad tracks near North 10th Street in Olney - stood just blocks from my parents' rowhouse.

Equipped with that one fact, my mind began to unwrap dusty memories as eagerly and hurriedly as kids used to tear open those packs of cards.

Fleer, I now remembered, was where several neighbors in Incarnation's parish worked. At least once, a friend's father brought home from there several freshly printed sheets of uncut baseball cards.

I also recalled stumbling upon that foreboding factory as a 6-year-old while exploring our extended neighborhood with the Dunn brothers, my much more daring pals.

The three of us stood that day on the crest of the 10th Street bridge that spanned the train tracks, transfixed by the sweet and seductive scent of gum.

No other sense, scientists tell us, is as adept as smell in summoning the past. And, like the baseball cards themselves, all these reawakened memories bore the aroma of chewing gum.

Despite that early introduction to the nearby wellspring of baseball cards, it wasn't until later, after the family moved west to Broomall, that I began collecting them.

Baseball cards were ubiquitous in the world postwar American kids inhabited. We bought them for a nickel a pack in drugstores, stowing the prized ones in shoe boxes we kept beneath our beds. When a renaissance hit the card business in the 1980s and many of them began to sell for thousands of dollars, a lot of us searched in vain for those boxes.

Cards were our currency. Almost always, we carried a rubber band-wrapped wad of them in our pockets. We showed them off, traded them, and - in what passed for pre-pubescent gambling - risked them by flipping or tossing them against walls.

"Baseball cards . . . were my first taste of capitalism," author Joe Pinsker wrote in a 2014 Atlantic piece on their place in American culture.

But culture changes, and by the late 1960s baseball cards were passé. By then Bowman's had been absorbed by its late-to-the-game New York rival, Topps. Fleer hung on longer, surged a bit during the 1980s boom, but disappeared in 2005, long after it had abandoned its Olney factory.

When my son collected baseball cards, he sheathed them in plastic cases and stored them away like rare coins. His son does the same. I doubt anyone carries them in their pockets or flips them anymore.

And I'm certain that when they opened those boxes of old cards from the Tennessee woman's attic, the gum didn't smell nearly as sweet.