(FORTUNE Small Business) – Entrepreneurial adrenaline ran high and hard at the 1893 Chicago World's Fair. Meant to be a post-frontier showcase of America's civilization and economic maturity, the expo was more than just a $27 million industrial trade show: It was an auspicious breeding ground for innovation that would carry the U.S. through the next century as a commercial leader. Thriving U.S. entrepreneurs and startups alike were encouraged to outshine and outdo their competition, and many of them hoped at the least to take advantage of the six-month running time to reach out to potential customers from all the corners of the world.

Some entrepreneurs, like Heinz, drew attention with their brash marketing. Others were less dramatic. There's not much to the story of Whitcomb L. Judson, who launched the world's first zipper from a corner of the Machinery Building. Boston cocoa purveyor Walter M. Lowney exhibited the first set of chocolate bars, but it's Milton Hershey (see following) who capitalized on them. And the fair also quietly brought the world the souvenir postcard, the first pay toilet, and beef bouillon. Among the more well-known debuts:

HEINZ'S PICKLE-PIN MANIA

H.J. Heinz used events like the fair to give people a chance to taste his products. Unfortunately for him, expo staff had consigned Heinz to an upper gallery tucked away in the Agricultural Building. Undaunted, Heinz hired some local boys to scatter small tickets all over the fairground. They read: "Finder will receive a souvenir at the Heinz booth." The resulting crowds, turning up to retrieve their Heinz-imprinted trinkets, were so overwhelming that the vendors on the first floor sued Heinz for unfair competition. And those on the second floor--who owed their foot traffic to Heinz--threw him a gala dinner.

BIRTH OF AMUSEMENT PARKS

From almost any point on the some 650 acres that hosted the exposition, fairgoers could glimpse a giant, rotating 264-foot wheel. Architect George W.G. Ferris, who invented the expo's icon, saw something that rivaled--and beat --Paris's exposition offering four years earlier, the Eiffel Tower. "What I've done is taken the Eiffel Tower, put it on a pivot, and made it move," he said. The wheel, undoubtedly the fair's biggest attraction, hosted weddings and private parties in its 36 rail-sized cabins, each of which could hold 40 people. The wheel cost riders 50 cents per two-revolution ride, and grossed $725,805--making it the only profitable investment for expo backers. But it was the culture of entertainment and free-wheeling freak shows at the wheel's base on the midway that would ultimately have the biggest impact on American society. It inspired modern-day amusement parks, starting with New York City's Coney Island in 1901.

AMERICA'S SWEET TOOTH

It was rumored that Milton Hershey, a caramel manufacturer from back East, would stand mesmerized for hours in front of a brand-new chocolate-making machine that had been brought over from Germany. The machine, along with the world's first chocolate bar, provided Hershey with all the inspiration he needed: He promptly bought the machine and returned home to Pennsylvania to concentrate on chocolate making. Then there was the German immigrant F.W. Rueckheim, who days before the fair had figured out how to "deglob" his unnamed molasses-coated popcorn and peanut confection, which three years later became known as Cracker Jacks. To wash everything down, Maine-based Rickers & Sons won top expo awards for its bottled Poland Spring Water. --MAGGIE OVERFELT