Some of the world’s most famous, civilization-altering discoveries happened by accident. Take Penicillin, for example. The guy who discovered it, Sir Alexander Fleming, simply forgot to clean up his work station one night and returned to discover the world’s first antibiotic growing right there in his unwashed petri dish.

But that’s not what this particular list is about. All the inventions here were invented very much on purpose – they just didn’t end up being used in the way their inventors had intended. Only after these inventions were repurposed – often in wildly unexpected ways – did they become famous, perhaps even civilization-alteringly so.

1. Listerine

Listerine was invented 133 years ago, first as a surgical antiseptic, but also as a cure for gonorrhea (don’t try that at home). An article from 1888 recommends Listerine "for sweaty feet, and soft corns, developing between the toes." Over the course of the next century, it was marketed as a refreshing additive to cigarettes, a cure for the common cold, and as a dandruff treatment. But it was in the 1920s that the powerful, germ-killing liquid finally landed on its most lucrative use as a magical cure for bad breath.

2. Propecia

Propecia, that ubiquitous drug used to treat male-pattern baldness, was originally marketed as Proscar, a drug to treat the benign enlargement of the prostate. After five years on the market in the 1990s, it became clear that one of the side effects of Proscar was – you can practically see the money signs flashing in the pharmaceutical marketers’ eyes – hair growth on bald men. Cha-ching!

3. Viagra

Viagra, or Sildenafil, as it's officially known, was originally conceived as a treatment for hypertension, angina, and other symptoms of heart disease. But Phase I clinical trials revealed that while the drug wasn’t great at treating what it was supposed to treat, male test subjects were experiencing a rather unexpected side effect: erections. A few years later, in 1998, the drug took U.S. markets by storm as a treatment for penile dysfunction and became an overnight success. It now rakes in an estimated $1.9 billion dollars a year.

4. Brandy

Brandy, that delightful, caramel-colored after dinner drink, started off as a byproduct of transporting wine. About 900 years ago, merchants would essentially boil the water off of large quantities of wine in order to both transport it more easily, and save on customs taxes, which were levied by volume. After a while, a few of these merchants, bored perhaps after a long day on the road, dipped into their inventory and discovered that the concentrated, or distilled, wine actually tasted pretty darn good. Voila! Brandy was born.

5. Coca-Cola

Coca-Cola, one of the world’s most famous brand names, was originally invented as an alternative to morphine addiction, and to treat headaches and relieve anxiety. Coke’s inventor, John Pemberton — a Confederate veteran of the Civil War who himself suffered from a morphine addiction — first invented a sweet, alcoholic drink infused with coca leaves for an extra kick. He called it Pemberton’s French Wine Coca. It would be another two decades before that recipe was honed, sweetened, carbonated and, eventually, marketed into what it is today: the most popular soda in the world.

6. Play-Doh

Play-Doh, that strange, brightly colored, salty clay that all of us grew up molding and poking (and, occasionally, nibbling), was first invented in the 1930s by a soap manufacturer named Cleo McVickers, who thought he’d hit upon a fantastic wallpaper cleaner. It wasn’t for another twenty years that McVicker’s son, Joseph, repurposed the goop as clay for pre-schoolers and called it Play-Doh, a product that remains wildly popular among the under-5 crowd today.